Archive of Our Own

Rimuru had never understood the appeal of romance. At thirty-seven years old, he considered himself completely immune to it. He spent his life watching friends get married, suffer through agonizing divorces, and weep over heartbreaks, always feeling like an outside observer watching a bizarre, incomprehensible cultural ritual. Love was a language he simply didn’t speak. He was perfectly content with his work, his single-bed apartment, and his quiet routines. In the grand ecosystem of Tokyo, Rimuru was a rogue planet drifting through life, entirely weightless, without a single gravitational anchor.

“Senpai, the others and I are gonna check out that new bar that opened nearby. You wanna come with us?” Tamura asked, leaning over the cubicle while Rimuru packed up his things.

Rimuru looked up at Tamura and pursed his lips. He liked the idea of a drink, but he despised the execution. Lately, it felt like all of his coworkers had suddenly started hooking up. Except for him, of course. Well, and Tamura and Sawatari, but they had been securely locked into their own predictable orbit since their college days.

If he went, the only pro was the alcohol. Work had been draining his battery lately, especially with the extra hours he spent hand-holding the clueless new hires. The con, however, was devastating. He was guaranteed to be marooned as a third wheel while everyone else dissolved into their respective lovers. Even Tamura, who always tried his best to keep Rimuru included, deserved to enjoy his time with his fiancée without babysitting a bachelor.

It wasn't that Rimuru was bitter. He genuinely didn't care. But he knew anyone with a shred of sanity would agree with him that public displays of affection were an atmospheric hazard.

“Oh, come on, Senpai! It’ll be fun!” Tamura insisted, catching the sour shift in Rimuru’s expression and instantly reading his thoughts. “And who knows? Maybe you’ll finally find someone there,” he added, wiggling his eyebrows suggestively.

Rimuru sighed, slinging his bag over his shoulder. “Yeah, right. I’m coming for the alcohol, Tamura, not to find the ‘love of my life.’”

“Ehhhh,” Tamura groaned, a profoundly confused look crossing his face. “Why, though? I really don’t get how you’re still single. It’s a literal waste. You have a small army of suitors!”

Tamura wasn’t exaggerating. Rimuru did have options - men and women alike. Blessed with an almost ethereal, androgynous beauty, long streams of light-blue hair, wide golden eyes, and flawless porcelain skin, people were drawn to him like moths to a flame. He was mistaken for a woman on a weekly basis. Some men backed off the moment they realized he was a guy, but the real freaks seemed to find it even more exciting. He usually ended up having to physically beat those types off. The women were less aggressive, usually expressing their interest through quiet gifts and left-behind treats, but no matter how sweet they were, Rimuru’s internal compass never pointed back. Romance was a completely alien concept.

“Just not my thing,” Rimuru answered flatly, steering them out of the office.

Tamura spent the entire walk to the reception desk lecturing him on the tragedy of his wasted ‘youth’, finally cutting it out when they picked up Sawatari. They made their way to the venue, which was already bursting at the seams. The air inside the bar was thick with ozone, sweat, and cheap perfume. Drunk bodies swayed to a live band on stage, and within five minutes, a few strangers tried to make sloppy advances toward Rimuru. Sawatari, catching the sudden spike of discomfort in his eyes, expertly boxed them out and sent them packing. Bless that girl, Rimuru thought.

The main floor was a chaotic sea of dancing and drinking, but luckily, one of their early-arrival coworkers had managed to secure a private room. Rimuru exhaled a breath of relief. He really didn’t want to navigate a room full of handsy strangers, nor did he want a drunk Tamura trying to aggressively wingman him.

The trio slipped into the sanctuary of the private room, where the table was already crowded with frosty pitchers of beer and fried finger foods. For the first hour, it was great. They screamed lyrics into the microphone, laughed as the rest of the team trickled in, and loudly complained about deadlines. But as the clock bled into the late night, the predictable shift occurred. The alcohol hit, the lights dimmed, and the room rapidly transformed into a hot zone of public displays of affection.

Rimuru cringed, his eyes darting away as another couple against the wall began aggressively exchanging saliva.

Nope. I’m out.

Setting his half-empty glass down, Rimuru quietly grabbed his coat and slid it on.

“Senpai, you’re leaving already?” Sawatari asked, tracking his movements over the rim of her glass.

“Wait, don’t—hic—don’t go yet!” Tamura stumbled backward as he stood up, reaching out a clumsy hand to anchor his senior.

“I, uh,” Rimuru rubbed the back of his neck, frantically scrambling for a believable lie. “I have to get home. My dog. If I don’t feed him soon, he’s going to literally tear my apartment to pieces.”

Sawatari and Tamura both raised an eyebrow in synchronized skepticism. They knew for a fact he didn't own a dog. Even a thoroughly wasted Tamura possessed that basic data point. But Sawatari caught the subtle tension in Rimuru’s shoulders and looked over at the couples melting into each other on the couches. She got it.

“Okay, Senpai. Go take care of your pup. Get home safe,” Sawatari said, giving Tamura a sharp, silent glare that instantly cut off his protests.

“Uh… yeah. Take care, Senpai,” Tamura mumbled, properly disciplined.

Rimuru gave them a grateful nod, scooped up his bag, and slipped out the door, entirely unnoticed by the rest of the intoxicated room.

When he finally unlocked the door to his apartment, the silence felt like a physical relief. He marched straight into his bedroom, shedding his coat and bag onto the floor like dropped cargo before collapsing face-first onto the mattress.

Ugh, I feel like I'm going to throw up, Rimuru groaned, burying his face into the pillows. The sheer cringe of the bar was turning his stomach. He truly, fundamentally did not get it. How could shoving your face against someone else's face be considered an enjoyable pastime?

He lay there in the quiet dark for a few minutes, letting his mind drift, when the hair on the back of his neck suddenly stood up.

The air in the room decompressed, dropping in temperature so fast his breath nearly hitched. A heavy, foreign presence suddenly occupied the small space. Rimuru bolted upright, spinning around, his eyes widening as they locked onto a figure standing dead center in his bedroom.

It was a tall man clad in an immaculate, tailcoat butler suit. He possessed sharp features and jet-black hair with streaks of crimson and gold in his bangs. But it was the eyes that paralyzed Rimuru. The sclera were an impossible, ink-like black, framing sharp pupils that glowed with a terrifying mix of crimson and gold.

He was gorgeous. Obliteratingly, jaw-droppingly handsome.

For a stupid, breathless second, Rimuru just gaped, his mind entirely blank, his jaw slightly slack.

Then reality slammed back into his brain. Intruder. This was a literal home invasion, no matter how much the guy looked like a high-fashion model.

“W-who the hell are you?! Why are you in my apartment? How did you even get in here?!” Rimuru yelled. He snatched a pillow from the bed, hoisting it like a weapon, but the stranger didn’t flinch. Instead, the man simply stared at him, his intense gaze shifting into profound confusion.

“Lord Rimuru?” the intruder murmured. His voice was a rich, velvet baritone that seemed to vibrate right through the floorboards.

“What?” Rimuru’s arm wavered, the pillow dropping a fraction of an inch. “How do you know my name?”

The man’s eyes suddenly ignited with blinding light. A brilliant, breathless smile broke across his face. Before Rimuru could even blink, the space in front of him fractured. The man was no longer standing in the center of the room, he was right there on the mattress, leaning in impossibly close, his gloved hands gently but firmly encapsulating Rimuru’s bare hands.

Rimuru let out a pathetic squeak, his entire face detonating into a furious blush. The proximity was dizzying. It was like the guy had literally teleported through a glitch in reality. That wasn't physically possible.

“My lord, it really is you!” the man breathed, his eyes practically sparkling with celestial devotion.

“H-huh?” Rimuru’s voice cracked. His brain was short-circuiting under the sheer pressure of the situation. “Are you… a stalker?” he managed to choke out. Every survival instinct told him to pull away, to scream, to kick, but he felt entirely locked in the man’s gravitational pull.

“Well…” The stranger paused, tilting his head as if genuinely analyzing the definition of the word. “No, my lord.”

Rimuru frowned, finally wrenching his hands out of the man’s grip and scrambling backward. “You sound entirely unsure! And what is with the ‘my lord’ nonsense?”

The man’s smile softened into something deeply fond. “You are my lord. My master.”

“Huh?!” Rimuru was losing track of how many times he had made that noise tonight. The world had gone entirely off the rails. The guy was clearly delusional. “I think you have the wrong apartment. I definitely don’t remember hiring a…” He gestured vaguely at the crisp vest and tie. “…a butler.”

The man didn’t argue. Instead, he smoothly glided off the bed and walked toward the window, throwing it open to look out at the Tokyo skyline. The flashing neon signs reflected in his dark eyes. “I see. So this must be the Otherworld.”

“What are you even talking about? You're making zero sense,” Rimuru said, watching him warily from the safety of his pillows.

The butler turned back, his expression deadly serious. “I am just as disoriented as you are, my lord. I am not supposed to be here.”

“Obviously,” Rimuru deadpanned. “Breaking and entering is usually frowned upon.”

“No, my lord. You misunderstand. I am not… supposed to exist in this dimension.”

Rimuru stared at him. Another dimension? Was this guy claiming to be an alien? He looked at the unique eyes, the otherworldly grace, the way he seemed to cut through the very fabric of the room. He certainly didn't look terrestrial.

Sighing, Rimuru rubbed his throbbing temples. Right. I'm just completely wasted, he reasoned. I got so drunk my brain is hallucinating a hyper-realistic, ridiculously hot cosplay actor in my room.

Slowly dragging himself out of bed, Rimuru walked over to the door. “Look, just come with me,” he said, twisting the knob. “You can explain whatever sci-fi movie you escaped from over some tea in the kitchen.”

They padded down the short hallway. Rimuru pointed to a chair at the small dining table, indicating for the stranger to sit while he began rummaging through the lower cabinets for his ginger tea. He desperately needed to flush the alcohol out of his system.

“My lord, allow me. Should I prepare the tea for you?”

The velvet voice materialized directly behind his left ear. Rimuru yelped in surprise, jerking upward so violently he would have cracked his skull against the underside of the counter if a firm, gloved hand hadn't instantly slid into the gap, cushioning the blow. Rimuru froze, his cheeks burning as he realized he was effectively trapped between the counter and the man's broad chest.

“N-no, it’s fine! I can manage,” Rimuru stammered, tightly clutching the cardboard box of ginger tea like a shield.

The man gently guided Rimuru back to a standing position, his touch light but unyielding. “I must insist, my lord. You look exhausted. Please, sit and relax. Permit me to serve you.” He gently escorted Rimuru over to the dining chair, pulling it out with practiced, effortless elegance.

Rimuru completely lost the will to fight. The man’s authority was magnetic, so he just sank into the chair, propping his elbow on the table and burying his chin in his palm. He watched, utterly mesmerized, as the intruder moved flawlessly around his cramped, messy kitchen. The man navigated the foreign space as if he had spent a lifetime serving tea in this exact spot.

A few minutes later, a perfectly steeped, steaming cup of ginger tea was placed gently in front of him. “Here, my lord.”

Rimuru muttered a stunned thank you, gesturing for the man to take the seat opposite him. The stranger complied, sitting with military posture. Rimuru picked up the mug, inhaling the rich, spiced aroma before taking a cautious sip. His eyes immediately went wide. “Whoa. This is incredible!” It tasted infinitely better than his usual microwave-and-teabag method.

The man beamed, a look of pure satisfaction washing over his features. “I am honored that it pleases you.”

Rimuru took a few more gulps, the warmth spreading through his chest and grounding him.

“By the way… um,” he trailed off, realizing he was hosting a supernatural entity and didn't even know his name. “What should I call you?”

The man chuckled, a dark, melodic sound that seemed to dance in the quiet kitchen. “Can you guess it?” he asked, leaning forward, his glowing red pupils locked onto Rimuru’s golden eyes with an intense, expectant gaze.

“Eh?” Rimuru scratched his cheek, sweating under the pressure. “I mean, give me a hint. What are you? What do you do?”

“I am a demon.”

Rimuru swallowed hard. The guy said it so casually, like he was announcing his blood type or his favorite color. A demon. Not an alien, a literal creature of the underworld. Did he accidentally summon something? He hadn't played with an Ouija board or read any sketchy poetry lately, though.

“Okay, okay,” Rimuru exhaled slowly, closing his eyes to sort through his muddled brain. A demon, right. What was the most generic, cliché demon name he could think of? “Hmm. Are you… Diablo?”

Rimuru immediately winced internally. Wow, great job, Rimuru. You picked the literal Spanish word for devil. How creative.

But across the table, the demon’s eyes went completely wide. Then, he threw his head back and let out a delighted, genuine laugh. “Kufufu… I suppose you truly are Lord Rimuru after all.”

Rimuru flushed. “Wait, so I was wrong?”

“Quite the contrary,” Diablo said, shaking his head as his laughter subsided, his eyes burning with renewed warmth. “My name is indeed Diablo.”

“No way,” Rimuru gaped, his jaw dropping for the third time that night. He had actually guessed it. “Okay, hold on. Why does me getting your name right prove anything? And how do you even know who I am? That’s what’s been driving me crazy.”

“Let us just say… that I know you from another world,” Diablo began, his tone shifting into something more narrative. “You are Lord Rimuru, yes. But you are not my Lord Rimuru.”

Rimuru blinked, trying to process the concept. “There’s another version of me running around somewhere?”

Diablo nodded, and over the next hour, he began to unravel a tapestry that felt entirely out of this world. He explained a dimension governed by magic, a world where a version of Rimuru ruled as a powerful Demon Lord (Wait, I’m a big shot over there?! Rimuru thought), and where Diablo served as his fiercely loyal secretary and butler.

When Rimuru asked how a demon ended up in a Tokyo apartment, Diablo explained the phenomenon of spatial distortions. Occasionally, tears in reality would abduct humans from this world and drop them into the magical realm. But this time, the physics had inverted, pulling a primordial entity out of his orbit and depositing him into the Otherworld.

Rimuru nodded along, his rational mind entirely giving up. If this guy was telling the truth, then all those ancient myths about oni and demons weren't myths at all. They were just dimensional immigrants.

“However, there is an anomaly,” Diablo murmured, his eyes narrowing slightly as he pondered the logistics.

“An anomaly? Aside from a demon making me tea?” Rimuru asked, taking a sip. At this point, nothing could shock him.

“Yes. If this is truly the Otherworld, you shouldn't exist here.”

Rimuru paused, setting his mug down. “What do you mean by that?”

Diablo was silent for a moment, his gaze turning incredibly complex. “Because according to my master, his original identity in this world was Mikami Satoru. He was stabbed, died, and subsequently reincarnated into our world, where he was bestowed the name Rimuru Tempest. Therefore, your presence here is a paradox.”

Rimuru scratched his head, his brain aching from the chronological whiplash. “Well… maybe this is just a parallel universe? An alternate version of the Otherworld?”

Diablo hummed, a slender finger tapping against his chin. “A multidimensional divergence. Yes, that is highly probable.”

Yeah, let’s just go with that, Rimuru thought. He had started the night trying to sober up, but this conversation was making him want to down an entire bottle of sake. “Okay, tell me more. What’s your world actually like?”

Diablo happily obliged, and before Rimuru knew it, hours had simply vanished into the vacuum of their conversation. By the time they stopped talking, the dark Tokyo sky had bled into a pale dawn.

“Great work today, everyone! See you tomorrow!” Rimuru called out, sweeping his documents into his bag with lightning speed. For the first time in his thirty-seven years of life, he had set a personal record for finishing his workload early.

“Senpai!” Tamura called out, jogging toward his desk with a thick stack of blueprinted papers. “Hey, can you look over these—”

“Sorry, Tamura! Can't do it! I have to get home to my dog!” Rimuru shouted over his shoulder, already throwing his coat on mid-stride. “Ask Rei-san or the chief! Bye!”

He sprinted out of the office before Tamura could even open his mouth.

Tamura stood frozen, staring at the empty doorway. “What dog…?” he muttered to himself, a memory sparking. “Didn't he use that exact same excuse at the bar?”

“Rimuru-senpai got a dog?” a nearby junior clerk asked, looking up from their computer.

Tamura just shrugged, utterly baffled. “Honestly, I have no idea. Maybe he did?” But something felt off. He made a mental note to text Sawatari about their senior’s increasingly erratic behavior.

Meanwhile, Rimuru was practically vibrating with adrenaline in the backseat of a taxi, urging the driver to hurry. He was excited to go home. It was a completely foreign sensation. For years, his apartment had just been a holding cell between shifts - a quiet, monochrome box. Now, he couldn't get back to it fast enough.

His mind flashed back to the previous night. Talking to Diablo had felt like experiencing missing time. The hours had just dissolved. He had learned so much about his alternate self - how they shared the same core personality, but one was a God-like entity and the other was just a tired contractor. He even found out that his late father, Veldora, who had passed away a year ago in this world, was alive and thriving as a literal Storm Dragon in Diablo's universe. Hearing that had brought a wave of bittersweet jealousy to Rimuru’s chest. His alternate self was so incredibly lucky.

But there was one detail that kept echoing in his head. Every single time Diablo spoke of the alternate Rimuru - who apparently was a literal slime - the demon’s entire demeanor would undergo a violent atmospheric shift. His dark eyes would ignite, a dark flush would creep onto his sharp cheekbones, and his voice would drop into a tone of absolute, intoxicating adoration. It was obvious that he was desperately, utterly in love with the slime Rimuru.

When Rimuru had bluntly pointed out the starry-eyed look, Diablo hadn’t even tried to deny it. Instead, he had smiled with immense pride and dropped a bombshell: “Well, of course, my lord. We are engaged.”

Engaged. Rimuru had literally choked on his own saliva.

So that was the root of it. That was why this terrifying primordial entity treated a mundane human contractor with such tender, ridiculous care. He was just projecting his love for the other Rimuru onto him.

The taxi driver’s voice jolted him out of his thoughts, announcing their arrival. Rimuru muttered a quick thanks, paid the fare, and practically flew up the stairs to his apartment.

He unlocked the door and stepped inside, instantly blinking in surprise. The apartment was immaculate. Every surface gleamed, the air smelled faintly of vanilla, and the clutter of years had been organized with terrifying precision. The perks of a demon butler, he thought, slipping off his shoes.

Before he could even set his bag down, Diablo materialized in front of him, causing Rimuru to flinch slightly.

“My lord! You have returned!” Diablo greeted, his voice practically singing with enthusiasm.

Rimuru took a moment to absorb the view. The formal butler uniform was gone. Instead, Diablo was wearing a simple black long-sleeve shirt and matching trousers - clothes that had originally belonged to Veldora. Rimuru had never been able to bring himself to throw them away after his father passed, never imagining they would be inherited by an interdimensional demon. Dad would probably find this hilarious, Rimuru thought with a small smile.

“I'm home,” he said. Then he noticed Diablo’s hands. Specifically, the smear of blue frosting on his long, elegant fingers. “What were you doing?”

“Oh, I was baking a cake,” Diablo answered.

“You know how to bake?” Rimuru asked, genuinely impressed.

“I learned from the best baker. Miss Shuna was an exceptional teacher.”

Right. Shuna. The oni princess Diablo had mentioned last night.

“But why make a cake today?”

A soft, beautiful smile graced Diablo’s lips. “Lord Rimuru has a profound fondness for sweets. I naturally assumed you would share that trait.”

Rimuru felt a strange, unfamiliar flutter in his chest. He quickly cleared his throat to hide his embarrassment. “Well, you’re not wrong. I love cake. Let me just change out of my work clothes and I’ll help you finish it.”

“There is no need, my lord. I can—” Diablo started, but Rimuru firmly shut his bedroom door, cutting off the demon's protest.

Rimuru quickly swapped his suit for a plain white t-shirt and comfortable black shorts, tying his long blue hair back into a loose, low ponytail. When he returned to the kitchen, Diablo was already applying the final touches of icing with meticulous care.

“Wow, you work fast,” Rimuru commented, leaning over the counter to get a closer look. “It’s almost done.”

Diablo paused his piping bag, turning his head to look at Rimuru. His gaze lingered, sweeping down Rimuru’s exposed collarbone, his bare legs, and the casual ponytail, before slowly returning to his face. “I did mention that I could handle it myself, my lord,” Diablo murmured, his voice suddenly sounding a bit thicker.

Caught under that intense, unearthly gaze, Rimuru’s cheeks flared a bright crimson. He shifted uncomfortably, suddenly feeling very naked in his oversized t-shirt. “Can you… stop with the ‘my lord’ stuff? It’s seriously embarrassing.”

Diablo froze for a second, then let out a low, amused chuckle.

“Wh-what’s so funny?” Rimuru squeaked, his defenses immediately going up.

“Nothing,” Diablo said, his eyes crinkling with deep amusement. “It is simply that this is the second time I have been scolded for that exact phrasing.”

Rimuru tilted his head, a heavy sensation settling in his stomach. “Let me guess. Your Rimuru told you the same thing?” It felt incredibly weird and slightly painful to say your Rimuru.

Diablo nodded, his eyes distant for a fraction of a second. “Indeed he did.”

“And I’m guessing you completely ignored him and kept calling him that anyway.”

“Correct again.”

“Figures,” Rimuru let out an amused, breathless sigh. “But if you guys are literally engaged, isn't it kind of stiff to keep calling him your master?”

Diablo’s smile turned slightly wicked, a dangerous, beautiful glint entering his eyes as he stepped a fraction closer. “In public, any other title feels like a demotion. He deserves nothing less than total worship. It has become our own unique endearment. However…” He leaned in, his voice dropping to a seductive whisper that sent a violent shiver down Rimuru’s spine. “…I do utilize a vastly different vocabulary when we are entirely alone.”

“A-alone time, right. Got it. Loud and clear,” Rimuru stammered, his face practically radiating heat. He aggressively gestured toward the cake to break the suffocating tension. “Just— finish the decoration, please!”

A few minutes later, the masterpiece was complete. It was a perfect cylinder coated in a smooth, vibrant light-blue frosting. On top, Diablo had used yellow icing to craft a neat little crown, with two simple black lines piped underneath.

Rimuru immediately whipped out his phone, completely charmed. “Oh, wow! It’s so cute! Is this a mascot character from your world?”

“That,” Diablo said, his voice brimming with affection, “is Lord Rimuru’s divine slime form.”

“Wait, really?” Rimuru stared at the cake, trying to visualize a round, squishy, blue blob wearing a crown. I’m a literal cartoon character over there, he thought, suppressed laughter bubbling up.

He snapped a quick picture and posted it directly to his Instagram story with the caption 'Best cake ever!' before bustling around the kitchen to grab two small plates, forks, and a knife.

Diablo cleanly sliced two perfect triangles. He refused to touch his own piece until Rimuru took the first bite, watching him with an intensity that made Rimuru feel like a test subject under a microscope.

Rimuru slid the fork into his mouth, and his eyes instantly shot open. “Mmm! Oh my god, this is incredible!” he moaned happily, immediately digging in for a second, larger bite. The texture was light as air, the sweetness perfectly balanced.

“Your praise is my highest reward,” Diablo said softly, finally taking an elegant bite of his own.

For a few minutes, the kitchen was quiet save for the scraping of forks. They couldn’t finish the whole thing, so Rimuru carefully wrapped the leftovers and slid them into the refrigerator.

As they stood side by side at the sink, washing the dishes together, the domesticity of the scene felt overwhelming to Rimuru. To break the suffocating, cosmic tension growing between them, Rimuru started asking questions about the magical world again, and Diablo eagerly fell back into his role as a storyteller, his velvet voice filling the quiet Tokyo night as the terrestrial world outside completely faded away.

“Do you want to go see some tourist spots?” Rimuru asked while they were rinsing off the dishes.

“Hmmm, do you have somewhere you can recommend?” Diablo asked, leaning in close as he dried a plate.

Rimuru hummed in thought. “Well, Mt. Fuji is a really famous landmark. Foreigners come from all over the world just to catch a glimpse of it. Maybe we should go camping at Lake Tanuki. The view of Mt. Fuji from there is breathtaking. I’ll schedule a trip the next time I get time off from work.”

“Alright. Whenever you are free, my lord.”

The next morning, Rimuru yawned heavily as he set his bag down on his office chair. Another day, another endless cycle spent trading his hours for a corporate paycheck. He was already missing the warm sanctuary of his bed (and the intoxicating presence waiting for him back at the apartment).

“Morning, Senpai!” he heard Tamura say, aggressively stepping into his cubicle.

“Morning, Tamura,” he greeted back, his voice still thick with sleep.

“So…?” Tamura said, wiggling his eyebrows and playfully elbowing Rimuru’s side.

“So… what? What is wrong with you today?” Rimuru asked, thoroughly confused.

“Is this…” Tamura started, sliding his smartphone out of his pocket. He scrolled rapidly through his apps for a moment before thrusting the glowing screen directly into Rimuru’s face. “...your ‘dog’?”

Rimuru stared at the screen. It was the picture of the blue slime cake Diablo had baked, which he had carelessly posted to his Instagram story the night before. He blinked at it for a few seconds, genuinely trying to remember what lie he had told Tamura about a pet.

“What are you talking about?” Rimuru deadpanned.

Tamura rolled his eyes dramatically, using his thumb and forefinger to zoom into the corner of the image before shoving it forward again.

Rimuru’s golden eyes widened. He stared at the screen, a cold sweat breaking out across his neck as he realized how badly he had messed up. When he had taken the photo, he had been entirely focused on how cute the cake looked, completely missing the fact that Diablo’s hand - long, elegant, pale hand - was clearly caught in the edge of the frame.

“So, who is the lucky guy?” Tamura asked cheekily.

Rimuru’s entire face detonated into a furious blush. “N-no! It’s not like that!”

“Uh-huh,” Tamura said, his tone dripping with absolute skepticism.

“He’s…” Rimuru glanced around the office nervously, his brain scrambling to manufacture a plausible alibi. He obviously couldn't explain that Diablo was a primordial demon from an alternate world. “He’s an old friend from Sendai! He came down to the city for a visit and he’s been staying with me for a bit.”

“Uh-huh,” Tamura repeated, a smug grin spreading across his face, much to Rimuru’s intense irritation. “A ‘friend,’ huh?”

“Yes. A friend.”

“Sure, sure. Whatever you say, Senpai,” Tamura said, clearly not believing a single word.

Thankfully, Tamura finally dropped the interrogation. But during their afternoon break, the subject flared up all over again. Apparently, the rest of his coworkers had seen his Instagram story too, and the office gossip mill was running at maximum capacity.

I should literally just deactivate my entire internet presence, Rimuru groaned internally, burying his face in his hands at his desk.

They relentlessly grilled him about the mysterious baker, and Rimuru stubbornly repeated the same ‘He's a friend from Sendai’ alibi. The rest of the team seemed to buy it, but Tamura kept throwing him deeply suspicious, knowing glances from across the room.

When night finally fell, Rimuru tore through his remaining tasks, packed his bag, and practically bolted for the exit.

“Oh, look at that. Senpai is finishing early again,” one of the junior clerks commented with a laugh.

Tamura gave him a knowing look. “Of course he is. He’s incredibly worried about his ‘dog’ back at home.”

Rimuru’s face flushed hot. He aggressively flipped Tamura the middle finger before slamming the office door behind him.

Rimuru used to possess a normal life. One that was grounded, safe, and entirely predictable. But meeting Diablo had felt like a violent, permanent shift in atmospheric gravity. He had been caught in an inescapable gravitational pull, yanked completely out of his own terrestrial orbit before he even realized his feet had left the ground.

Over the next few weeks, Rimuru found himself structurally dismantling his work habits, completing his projects with frantic speed just so he could hurry back to the apartment. He discovered, much to his own quiet terror, that he had grown entirely addicted to the demon’s smothering, doting nature. He liked being taken care of. He liked the worship, even though a dark, agonizing voice in the back of his mind constantly whispered that it was a stolen luxury - that Diablo was only pouring this cosmic devotion into him because he shared a face and name with the demon’s true master and lover.

The time they spent together in that cramped Tokyo flat didn’t feel like regular daylight. It was bioluminescent - a strange, glowing neon that only thrived in the dark, safely hidden away from the rest of the world. Together, Rimuru and Diablo had engineered their own unique atmospheric pressure within those four walls, a climate made only for the two of them to breathe.

When Rimuru’s hard-earned vacation days finally arrived, he kept his promise and took Diablo to Lake Tanuki to see Mt. Fuji. They spent the weekend living in a beautiful, weightless slipstream - cooking over the campfire, taking photos of the pristine landscape, fishing, and laughing as Diablo awkwardly learned how to play with the local children.

Naturally, the two of them attracted an immense amount of attention at the campsite. To the casual observer, they looked like an impossibly attractive, hyper-fashionable couple. The only thing that drew puzzled glances was Diablo’s eyes, which they smoothly explained away as a highly specialized scleral tattoo. The campers looked at Diablo in absolute awe, whispering about how brave he must have been to endure getting his eyes tattooed. Rimuru just had to bite his tongue to keep from laughing. If only they knew.

On their second afternoon, they rented bicycles. Rimuru spent an hour teaching Diablo how to balance, though he shouldn't have been surprised by how rapidly a primordial entity adapted to human mechanics. Within no time, they were racing each other.

They spent the twilight hours riding in lazy, beautiful circles around the perimeter of Lake Tanuki. At one point, Diablo looked back over his shoulder, his midnight-black hair whipping in the wind, and flashed Rimuru a smile of such pure, unadulterated happiness that Rimuru felt the breath completely leave his lungs.

In that exact microsecond, Rimuru knew he had crossed the event horizon. There was no turning back, no saving himself. He had slipped past the point of no return, falling helplessly, irrevocably into the demon.

By the fifth month, their lives had merged into a beautiful, nameless routine. They went out constantly whenever Rimuru had a day off, yet they still hadn't defined what they were. They existed as a nebula - a swirling, colorful, chaotic cloud of late-night conversations, shared secrets, and unformed potential, waiting for a catalyst to make them collapse into something solid.

Whenever they were together inside the apartment, it felt like entering a singularity - a lawless space where all the normal rules of earth, logic, and self-preservation collapsed into absolute nothingness. The outside world ceased to exist.

Yet, a profound anxiety choked Rimuru. He had no idea how to tell Diablo that he had fallen in love with him. He hadn't chosen this path. Diablo simply possessed a mass that a mere human couldn't compete with - a silent, magnetic pull that dragged Rimuru’s eyes, his steps, and his entire heart directly into the demon's trajectory. Part of him burned to scream it aloud, another part was paralyzed by the incoming tragedy. He felt so incredibly stupid for letting his defenses drop, knowing with absolute certainty that Diablo was a temporary visitor. He didn't belong here. He belonged to another universe. He belonged to the other Rimuru.

The breaking point arrived on a rainy Friday night. Unable to carry the weight of his own silence anymore, Rimuru asked Diablo to drink with him. He drank aggressively, drowning his anxieties in alcohol until Diablo’s expression tightly laced with worry. But Rimuru just waved his concerns away, pouring another glass.

“Di-Diablo… I—” Rimuru hiccuped, the alcohol stripping away his lifetime of inhibitions. He scrambled across the couch, recklessly climbing onto the demon’s lap and straddling his thighs. He leaned in until their lips were almost brushing. “I’m in love with you.”

Diablo’s eyes widened in shock before quickly softening, his large hands instinctively coming up to steady Rimuru’s hips. “You are heavily intoxicated, my lord. We should get you to bed.”

“No!” Rimuru shouted, gripping Diablo’s shoulders with white-knuckled intensity. “Let’s talk about this… please…” he begged, his voice suddenly fracturing into something incredibly small and desperate.

“We can discuss whatever you wish once you are sober,” Diablo countered gently, attempting to lift him, but Rimuru fiercely shook his head.

Driven by a sudden, agonizing wave of need, Rimuru lunged forward and crashed their lips together.

It was a messy, desperate, entirely inexperienced collision. Diablo froze, taken completely aback by the sudden friction. But as the human on his lap let out a soft, whimpering noise, pressing closer with a raw, heartbreaking neediness, the demon’s restraint snapped. His grip on Rimuru’s hips tightened, and he began to kiss him back.

They melted into each other on the couch, pulling apart only to gasp for oxygen before diving right back into the heat. Rimuru’s mind devolved into a beautiful, hazy blur. For years, he had judged his coworkers for losing their minds over something as simple as exchanging saliva, but now, caught in Diablo’s mouth, he finally understood the terrifying appeal.

Before he could process the shift, the space fractured. Diablo teleported them directly onto the bedroom mattress, smoothly hovering over Rimuru’s body. The demon looked down at him, taking in how flushed, disheveled, and breathtakingly beautiful the blue-haired man looked beneath him. Diablo reached out, tenderly tucking a loose strand of hair behind Rimuru’s ear.

“My lord, I truly do not wish to take advantage of you while you are not in your best condition,” Diablo whispered, his voice thick with suppressed restraint. “Let us stop here. Permit me to just hold you while you sleep.”

“No, Diablo, please…” Rimuru wept, reaching up to yank aggressively on the demon’s collar, pulling their faces close. Hot tears spilled from the corners of his eyes, tracing paths down his porcelain skin. His entire body was aching with a profound, terrifying hunger. He needed this mark on his history. He needed Diablo now, even if it ruined him forever. “Don't leave me out here in the cold.”

Diablo let out a low, defeated groan before entirely giving in, leaning down to capture Rimuru’s lips with an intensity that made the room spin.

Within minutes, their clothes were discarded onto the floor. They admired each other’s naked forms in the dim light before joining their bodies as one, establishing a rhythm. Under Diablo’s burning, unearthly gaze, Rimuru felt exposed - like he was lying on an operating table under blinding lights, with the demon dissecting his entire thirty-seven years of isolation without touching a single memory.

In this space, there was no master and no servant. They existed as binary stars, locked in a flawless, luminous dance around a shared center, holding each other up in the vast, empty dark without either one ever dimming the other. Rimuru clung to Diablo so tightly he could barely draw breath, but the air on Diablo's planet tasted so much sweeter than Earth’s ordinary oxygen that he didn't care if he suffocated.

When the final, blinding release tore through them, they collapsed against each other. Diablo pulled Rimuru flush against his chest, wrapping his arms around his waist and gently petting his damp hair.

“I am sorry, my lord,” Diablo murmured into the quiet darkness, his voice laced with an unbearable weight. “But you must know… I cannot stay in this world.”

But Rimuru never heard the confession. Exhausted and thoroughly spent, the blue-haired man was already fast asleep, his breathing deep and even against the demon’s chest.

The next morning, Rimuru woke up to absolute, crushing stillness.

He was naked. And he was entirely alone.

Slowly dragging himself out of bed, he wrapped the bedsheets securely around his body like a shroud and began padding through the quiet apartment.

“Diablo…?” he called out, his voice echoing off the walls. No answer.

He searched every single square inch of the flat. The kitchen was empty. The living room was immaculate. There was no sign that a supernatural entity had ever occupied the space.

Suddenly, the cold, brutal reality slammed into his chest like a physical blow.

Diablo was gone.

No note. No parting explanation. Nothing.

He had vanished just as abruptly as he had arrived, leaving Rimuru’s life completely hollowed out. He had undoubtedly found his way back to his true world. Back to his Rimuru.

The air in the apartment suddenly felt too thick to breathe. Rimuru sank to his knees in the middle of the living room floor, clutching the bedsheet tightly around his bare shoulders as violent, agonizing sobs ripped from his throat. He wept until his chest burned, entirely ruined by the silence.

He called in sick to work that day, spending the next seventy-two hours staring at the ceiling, paralyzed by exhaustion and grief. When he finally forced himself back to the office three days later, the change in him was devastating. The vibrant, ethereal energy was gone. He stopped rushing to finish his projects early, instead volunteering for grueling hours of overtime just to avoid going back to an empty apartment.

Tamura tried to tease him on his first morning back, asking with a grin how his "dog" was doing.

But when Rimuru turned to him with dead, hollow eyes and whispered, “The dog is gone,” Tamura’s smile instantly vanished. He recognized the look of a shattered heart. Even without knowing the details, Tamura felt a wave of protective rage toward whoever that mysterious Sendai visitor had been. How dare he abandon someone as wonderful as their senpai?

Tamura and Sawatari began forcefully dragging Rimuru out after hours, trying their absolute best to distract him, to make him forget. Rimuru was profoundly grateful for his friends, but the black hole Diablo had left behind in his chest was simply too vast to be filled by ordinary human kindness.

His other coworkers occasionally asked what happened to the man from his Instagram, but Rimuru tightly locked his lips. He finally understood the tragedy of people who claimed to have been abducted by aliens or witnessed UFOs - nobody ever believed them. They were laughed at, labeled as crazy, or pitied as delusional. Rimuru knew if he ever spoke Diablo’s name aloud, the world would treat him the exact same way.

The five months he had shared with Diablo were never meant to age gracefully into a quiet retirement. It was a supernova. They had burned through a lifetime of passion in a single season, blinding everyone around them, until there was nothing left to do but explode.

Diablo's presence in his life had been a spectacular meteor shower - brief, breathtaking, and entirely temporary. He had streaked through Rimuru’s darkest, most isolated season, lit up his entire horizon, and vanished before Rimuru could even find the vocabulary to beg him to stay.

Dropping back down to Earth had scorched everything Rimuru had left. Now, he walked those terrestrial, gray Tokyo streets, looking at normal people living normal lives, wondering how on earth they could stand being so horribly weighted to the ground.

His chest ached daily with the brutal decompression sickness of having to breathe regular oxygen again. Diablo had left his life completely cratered - a barren, cold moonscape where nothing else would ever grow. He had been ruined for Earth, left with nothing to do but walk through his ordinary routine, constantly looking up at the night sky, desperately waiting for the spaceship to come back and take him home.

Rimuru slowly blinked his eyes, his vision swimming as the heavy fog of sleep began to lift. Through the blur, he could make out a familiar figure with long purple hair and a prominent horn leaning over him.

“Lord Rimuru!” Shion gasped, her face lighting up. “You’re finally awake!”

“Shi…on?” Rimuru mumbled, his voice incredibly raspy. He rubbed his eyes to clear his vision, pushing himself up into a sitting position as he looked around the room. “What are you doing in my private quarters?”

Shion’s eyes instantly filled with massive tears. “I’m going to tell everyone right now that you’ve finally awakened!” she cried, completely ignoring his question as she spun on her heel and bolted out the double doors.

Rimuru stared at the empty doorway, thoroughly bewildered. He groaned, burying his face in his hands. His head was pounding with a vicious headache, and his magicules felt strangely sluggish. He felt as though he had been asleep for a century.

Suddenly, the doors flew open again, and a small army of his executives came bursting into the room, all of them looking visibly tear-stained and breathless.

“Lord Rimuru!” they cried out in unison, instantly dropping to their knees in front of his bed.

“We are so grateful that you have returned to us!”

“Uh, what exactly is going on here?” Rimuru asked, tilting his head.

Suddenly, Raphael's voice resonated within his mind.

[Answer: You have been trapped in a deep slumber for exactly five months.]

Five months?! Rimuru thought, his mind short-circuiting.

Then, like a dam breaking, a tidal wave of memories came crashing into his consciousness. He remembered everything. He remembered missing the simple human sensation of sleeping and dreaming, and how he had explicitly ordered Vesta to research a specialized sleeping pill for him.

Ah. The dream. Memories of a cramped Tokyo apartment, a corporate job, and a thirty-seven-year-old human existence flooded his mind. It felt so hyper-realistic. A sweet, deeply tragic, and heartbreakingly beautiful dream.

“I am so deeply sorry, Lord Rimuru,” Vesta stepped forward, his eyes glued to the floor in profound shame. “I should never have given you an incomplete, unrefined prototype—”

“No, no, no! You’re totally fine, Vesta! Don’t worry about it!” Rimuru interrupted hastily, waving his hands around to diffuse the heavy guilt in the room. “It’s entirely my fault. I was stupid and took three pills at once.”

[I explicitly warned you. You should have permitted me to nullify the chemical composition of the medicine.]

Alright, alright, I’m sorry, Raphael-sensei! Cut me some slack! Rimuru fired back internally. He cleared his throat, addressing his worried subordinates. “So, uh… who was running Tempest while I was out cold?”

“Lord Veldora took up the mantle of leadership in your absence, Lord Rimuru,” Souei answered.

Speak of the devil. The moment his name was uttered, the doors rattled as Veldora marched into the room with maximum dramatic flair.

“Kahahahaha! I have heard that my son has finally broken his slumber!” Veldora boomed, crossing his arms proudly.

Rimuru stared at the blonde dragon for a long, silent moment. For some bizarre reason, a sudden wave of intense emotion hit him, making his eyes sting. It felt like looking at a ghost. In that strange, human dream, his father had been dead for a year.

Before anyone could react, Rimuru launched himself out of the bed and threw his arms tightly around Veldora’s neck. “Dad…” he choked out, the word slipping out before he could catch it.

Veldora blinked in surprise, but quickly let out a hearty chuckle, wrapping his arms around Rimuru. “My, did you truly miss me that much over a simple nap?”

Rimuru just nodded into Veldora’s shoulder, clinging to him with a fierce intensity. They stayed locked in the embrace for a long moment while the executives watched the unusually sentimental reunion with touched expressions.

“Thank you for protecting the nation while I was gone,” Rimuru murmured, finally pulling back with a soft smile.

“Of course! You can always rely on the Great Veldora! Kahahahaha!”

“Um…” Rigurd suddenly interjected, stepping forward with a look of extreme hesitation. “Lord Rimuru, we do have one pressing crisis that occurred during your slumber.”

Rimuru turned his attention to the Goblin King. “A crisis? What is it?”

“Sir Diablo has been missing for the past five months.”

“What…?” Rimuru felt his stomach instantly drop. No. That couldn't be right.

“Hmph,” Shion huffed, crossing her arms in annoyance. “That eccentric man vanished into thin air the exact same day you fell into your deep sleep, Lord Rimuru.”

Rimuru whipped his head toward her. “He what?”

Before anyone could answer, a violent crack echoed through the room. The air in the center of his private quarters literally fractured, spinning into a localized spatial distortion that blossomed into a dark, unstable portal.

A figure tumbled out of the rift, hitting the floor before the portal instantly snapped shut, vanishing into nothingness. Rimuru’s breath caught in his throat as he took in the newcomer’s appearance. The immaculate, formal butler attire was completely gone. Instead, Diablo was clad in a thoroughly wrinkled, ordinary human sweatshirt and matching casual trousers - the exact clothes Rimuru had preserved in his dream.

Diablo pushed himself up from the floor, his black-and-gold eyes scanning the room wildly until they locked onto Rimuru’s golden ones.

In an instant, the demon’s entire expression shattered. The terrifying, primordial entity looked like he was on the absolute verge of tears.

“My lord…” Diablo whispered, his voice trembling as he took a fragile, hesitant step forward.

“Diablo! Where have you been? I just heard that you—” Rimuru started, but he was completely cut off.

In a blur of impossible speed, Diablo crossed the distance, throwing his arms around Rimuru and pulling him violently against his chest. He held him with a crushing, desperate grip, as if terrified that if he let go, the universe would rob him of his master all over again.

“I am so sorry,” Diablo choked out, burying his face deeply into Rimuru’s light-blue hair. He was shaking. “I am so incredibly sorry, my lord.”

“H-hah? Why are you apologizing?” Rimuru stammered, entirely caught off guard by the demon's sheer vulnerability.

“I am sorry for suddenly vanishing from your side. I did not mean to leave you. I was—”

“Hey, hey,” Rimuru said softly, his voice melting into profound warmth. He gently pushed against Diablo’s chest just enough so he could look the demon dead in the eye. He saw the sheer terror and devotion burning in those crimson pupils, and a realization sparked in his mind. It wasn't a dream. He was really there with me. “I get it, alright? I understand completely. I know you would never leave me without a reason.”

“I will never leave your side again. Never. Not for a single second,” Diablo declared, his voice ringing with a terrifying, beautiful vow of eternal devotion.

“I know,” Rimuru replied, a beautiful smile gracing his lips. Standing up on his tiptoes, he reached up and gently pressed a soft, reassuring kiss directly onto the demon's lips.