Chapter Text
Tengen Uzui had three fundamental rules for living his best life:
One: Everything he owned had to be aesthetically flamboyant. Two: His penthouse apartment was a pet-free zone. Three: He never, ever got emotionally attached to things that couldn't appreciate his fabulousness.
So naturally, when he found two bedraggled cats huddled in a cardboard box outside Kimetsu Academy on a rain-soaked Tuesday evening, his first instinct was to keep walking.
"Not my problem," he muttered, adjusting his designer sunglasses despite the overcast sky. His white hair was pulled back in his signature style, and his multiple ear piercings glinted as he turned away from the pitiful mewling sounds.
He made it approximately three steps.
The smaller cat—a scrawny orange kitten with enormous eyes—let out a cry that sounded disturbingly like a child's sob. Tengen's eye twitched. He was the Art teacher at Kimetsu Academy, not an animal rescue service. He had lesson plans to finalize, an exhibition to curate, and absolutely zero interest in—
The larger cat, a magnificent flame-patterned tomcat with bright golden eyes, nudged the kitten closer to its body and stared directly at Tengen with an intensity that felt almost human.
"Oh, for the love of—" Tengen groaned, running a hand down his face. "This is not flamboyant. This is a disaster."
Five minutes later, he was carrying a soggy cardboard box into his BMW, mentally calculating how quickly he could drop these fleabags at the nearest shelter. The larger cat watched him with those unsettling golden eyes the entire drive, while the kitten had curled into a tight ball, shivering.
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Tengen's apartment was a masterpiece of modern design—all clean lines, carefully curated art pieces, and a color scheme of burgundy, gold, and cream that he'd spent months perfecting. The cats looked like a natural disaster waiting to happen.
"Okay, ground rules," he announced, setting the box down on his pristine marble floor. "You're here for ONE night. Tomorrow, I'm taking you to a shelter. Do NOT scratch anything. Do NOT puke on my Persian rugs. And absolutely do NOT get comfortable."
The large cat stepped out of the box with surprising dignity, immediately beginning to groom the smaller one. Up close and dry, Tengen could see the larger cat was actually quite stunning—red and gold fur that blazed like fire, with white markings on its chest and paws. The kitten was more subdued in coloring, orange and cream, but clearly younger and more fragile.
Against his better judgment, Tengen found himself pulling out some leftover grilled chicken from his fridge.
The cats devoured it with desperate hunger that made something uncomfortable twist in his chest.
"Don't look at me like that," he told them. "This doesn't mean anything. I'm not a cat person. I'm barely a people person."
The large cat tilted its head, then did something that made Tengen freeze—it sat up straight, placed one paw over its chest, and seemed to... bow?
"What the—" Tengen shook his head. "Okay, I'm clearly more tired than I thought. Cats don't bow."
He set up a makeshift bed using an old blanket in the corner of his living room, as far from his furniture as possible. The cats settled in immediately, the larger one curling protectively around the smaller. Despite himself, Tengen found his phone in his hand, snapping a photo.
For documentation purposes only, he told himself. In case they turned out to be someone's lost pets.
He absolutely did not send it to the Kimetsu Academy staff group chat with the caption: "Anyone lose two furballs? Found them outside the school. Keeping them TEMPORARILY."
His phone buzzed almost immediately.
Shinobu Kocho: Oh my, how responsible of you, Uzui-san! 🦋
Giyu Tomioka: cats are good
Sanemi Shinazugawa: fucking typical. mr flashy cant handle a little responsibility
Tengen Uzui: I CAN handle responsibility. I'm CHOOSING not to. Big difference.
Mitsuri Kanroji: THEY'RE SO CUTE!!! 💕💕💕 The big one looks just like Rengoku-san's coloring!!!
Tengen glanced at the flame-patterned cat, then at Mitsuri's message. Huh. She wasn't wrong. He'd never really paid attention, but the Academy's perpetually enthusiastic History teacher did have that same golden-red color scheme going on.
Speaking of which...
Tengen Uzui: Has anyone heard from Rengoku? He missed the staff meeting yesterday.
Shinobu Kocho: No response to my messages. Most unlike him.
Gyomei Himejima: I am concerned. Rengoku-san is never this quiet. I shall pray for his wellbeing.
Sanemi Shinazugawa: probably got food poisoning from eating too many sweet potatoes
Tengen Uzui: What about the kid? Senjuro?
Muichiro Tokito: absent from class. both days
A strange feeling settled in Tengen's gut. He looked at the two cats—one large and protective, one small and vulnerable. Brothers, maybe?
"Nah," he said aloud. "That's insane."
The large cat's ear flicked, and for just a moment, Tengen could have sworn it looked... guilty?
He really needed to get more sleep.
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The next morning, Tengen woke to find the large cat sitting on his chest, staring at him from approximately two inches away.
"JESUS—" He flailed, nearly falling out of bed. "Personal space! That's a thing!"
The cat didn't move, just continued staring with those intense golden eyes. Then, deliberately, it reached out one paw and patted Tengen's cheek. Gently. Almost... apologetically?
"This is fine," Tengen muttered. "This is totally normal cat behavior. I'm not going crazy."
He tried to go about his morning routine, but the cats followed him everywhere. When he showered, they sat outside the bathroom door. When he made coffee, the large one jumped onto the counter (leaving muddy paw prints on his granite, fantastic) and watched him with fascination. When he tried to get dressed, the kitten somehow ended up tangled in his pants.
"This is why I don't do pets!" he announced to his empty apartment. "You're chaos incarnate!"
But when he looked down at the kitten, now freed from his designer slacks and looking up at him with huge, apologetic eyes, he felt his resolve wavering.
"One more day," he heard himself say. "Just until I can get to the shelter. They're probably closed on Wednesdays anyway."
They were not closed on Wednesdays. He checked.
He still didn't take them.
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At school that day, Tengen found himself distracted. His first-year students were working on perspective drawings, but he kept thinking about whether the cats had enough water. Whether they were scared, alone in his apartment. Whether the kitten was warm enough.
"Uzui-sensei?" One of his students, Tanjiro Kamado, raised his hand. "Are you feeling alright? You seem worried."
"I'm fine," Tengen said automatically. Then, because Tanjiro had that annoyingly earnest way about him that made people spill their guts, he added, "I found some stray cats yesterday. They're at my place."
The entire class perked up.
"Cats?!" Zenitsu Agatsuma shrieked. "Uzui-sensei has CATS?!"
"Temporarily," Tengen emphasized. "Very temporarily."
"What do they look like?" Inosuke Hashibira demanded, standing on his desk for no apparent reason. "Are they fierce? Can they fight?!"
"Get down, Hashibira. One is... red and gold. Kind of dignified-looking. The other is smaller, orange and cream."
Tanjiro's eyes widened. "Red and gold? Like fire?"
"I guess?"
A strange look passed over Tanjiro's face, but before Tengen could question it, Shinobu Kocho appeared in his doorway.
"Uzui-san, a moment?" Her smile was pleasant, but her eyes were calculating. "It's about Rengoku-san and his brother."
Tengen's stomach dropped.
In the hallway, Shinobu's smile faded. "I went to their house this morning. No one answered, but the door was unlocked. There were signs of a struggle in Rengoku-san's study—books everywhere, and..." She pulled out her phone, showing him a photo of a strange, shimmering powder scattered across the floor.
"This."
"What is it?"
"I'm not certain. But I found this too." She swiped to another photo—a torn piece of paper with writing on it. "It's a receipt from that occult shop downtown. 'Demon Slayer Mystical Goods.' The date is from three days ago."
"You think Rengoku went to some hack magic shop?" Tengen raised an eyebrow. "That doesn't sound like him."
"It was for Senjuro's birthday," Shinobu said quietly. "Apparently he wanted to get him something 'special and unique.' The shop owner remembered them. Said they bought something called a 'transformation charm' as a joke gift."
The pieces clicked together in Tengen's mind with horrifying clarity. The cats appearing the same day Rengoku and Senjuro disappeared. The larger cat's oddly human mannerisms. The coloring. The way it seemed to understand him.
"No," he said. "Absolutely not. That's insane."
"Is it?" Shinobu tilted her head. "Stranger things have happened. Remember when Douma-san claimed he saw a 'rainbow demon' and ended up hospitalized with hallucinogenic mushroom poisoning? He spent six hours trying to convince the ER staff he could taste colors. They had to sedate him when he started licking the walls."
Despite everything, Tengen snorted. That had been hilarious. The faculty group chat had been gold that day.
"Even if—and this is a massive if—those cats are somehow Rengoku and his brother, what am I supposed to do about it?"
"Keep them safe," Shinobu said simply. "Until we figure out how to reverse it. I'm researching the shop now, but these things take time. Can you handle it?"
Tengen thought about his pristine apartment. His carefully maintained bachelor lifestyle. His absolute insistence on remaining unattached and fabulous.
Then he thought about that scrawny kitten, shivering in the rain.
"Fine," he sighed. "But they owe me. Big time."
Shinobu's smile returned, sharp and knowing. "I'm sure Rengoku-san will be very grateful when he's human again."
Something in her tone made Tengen's ears burn, but he refused to acknowledge it.
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When he returned home that evening, armed with actual cat supplies (gourmet cat food, because he refused to be that guy, a proper litter box, toys that looked sufficiently flamboyant), he found the cats had redecorated.
His throw pillows were arranged in a neat circle. His art books were pulled from the shelf and stacked by subject. And the large cat was sitting in front of his sound system, having somehow turned on one of Tengen's classical music playlists.
"Okay," Tengen said slowly. "We need to talk."
The large cat's ears perked up.
"If you're who I think you are—and I'm not saying I believe it, because this is objectively bonkers—meow once for yes, twice for no."
The cat stared at him for a long moment. Then, very deliberately, it meowed once.
The kitten scurried over and also meowed once, as if agreeing.
Tengen sat down heavily on his couch. "Rengoku? Is that actually you?"
One meow.
"And that's Senjuro?"
One meow from both cats.
"How the hell did this happen?"
The large cat—Kyojuro, apparently—pawed at the air in a helpless gesture. The kitten made a sad, trilling sound.
"Right. You can't exactly explain." Tengen rubbed his temples. "Okay. Okay. This is fine. I'm harboring my colleague and one of our students as cats. Totally normal Thursday."
Kyojuro padded over and bumped his head against Tengen's hand. It was warm and solid and somehow comforting.
"Don't get used to this," Tengen muttered, but he was already scratching behind Kyojuro's ears. The resulting purr was embarrassingly loud. "I'm still not a cat person."
Senjuro joined them, curling up in Tengen's lap. Within minutes, both cats were asleep, and Tengen was trapped under a pile of warm, purring feline.
He pulled out his phone and took another photo. This time, he didn't share it with anyone. This one was just for him.
End chapter 1