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Gotham’s got DEMONS

Summary:

Gone are the days of demons and demon slayers, Muzan was killed in the final battle and the humans had prevailed. Lives were lost, but justice had been served. All of the remaining demons perished when their connection to the demon king was severed. At least... That was for everyone except two. Yushiro Yamamoto, and his demon cat, Chachamaru, the last two demons on earth. They lived long past everyone who survived the era of demons except for the oldest man in the world, Kiriya Ubuyashiki. But, he was an old man whose stories were made up by someone who had long lost his mind to old age.

Yet they were true.

After crossing paths with a woman who looked identical to his past partner, Tayamo, and the industrial boom of Japan, Yushiro packed his stuff along with Chachamaru and left for the hills. Or rather, left for Gotham, a city in the Americas, better known as “the crime capital of the world.” Now he's trying to make it by living in a city of crime. It's easy for a demon like him to slip in and stay hidden. At first it was just an unregulated and a poorly policed place, but then Batman began his reign. And soon the robins came as well.

TLDR - Yushiro is old.

Notes:

This is my first fic on AO3... I know this crossover is very niche, but that's how I like my fics. Anyways, this is really just an introduction chapter, very easy, nothing major.

I have attached a document to this chapter! This is a doc that will hold Ages, heights, and birthdays of all the characters involved in the fic AND two photos of height comparisons. In the future I will be putting an FAQ section but for now it’s just a waiting game.

https://docs.google.com/document/d/1-yPgUKY5dUF_R5Po7WvgUYraFes9uPmfbwDgwXMM7aM/edit?usp=drivesdk (This is the document link)

You can find me on TikTok at @mrscheesess (I am a rant account, so beware.)

(See the end of the work for more notes.)

Chapter 1: It's a long, hard dusty road

Chapter Text

Crunch.. Crunch.. Pat.. Pat.

 

The sound of soft footed boots barely echoed off the wet alley walls. The soft pattering of an animal following close behind. A young man covered in a black rain jacket, the hood obscuring the man's facial features and the long fabric removing any identifiable proportions. The hooded figure approached a slumped man against the alley wall. Red splattered behind him, circling where the man's head had been like a halo of death.The now sticky liquid washed into a drain from the unrelenting rain, his face mangled by a brutal bullet that laid discarded and disfigured to the side. A suicide? Possible. But, seeing as no gun lay in the man's hand, the best conclusion had to be murder. 

 

The man in the dark jacket did not waver, accustomed to the weight of death.

 

The shadows that covered his face faded as a nearby street light flickered in the rain. His skin was pale as snow, his eyes an unnatural purple with cat-like pupils. A few pale green hairs tipped with black fell down from under the hood. Reaching for the body in silence came naturally, years of practice kept his nerves at bay. With slight, disgusted, hesitation he reached for a pulse.You never know with these humans, some refuse to die. 

 

After quickly cleaning off his fingers with a pocketed tissue, he wasn't shocked that the man was dead. 

 

Pulling a syringe attached to a large vial out of his pocket, he hovered it just above the dead man's arm. Waiting…

 

Mrow!

 

 His gaze turned towards a small calico cat beside the man's feet. Yellow eyes and large pupils staring intelligently at him. Their white maw stained red as a feline sized bite was missing from the guy's leg. Chachamaru had given him the stamp of approval, the freshly killed man was fine for consumption. With a soft nod of acknowledgement to his friend, he sunk the end of the needle into a slowly dulling vein. Prefect, there was still fresh blood in the man's veins. The demon watched carefully as the vail filled with the thick crimson liquid. His purple eyes staring at his warped reflection. 

 

To whatever god is out there- how the hell did he end up here? Oh right, It was that kid’s fault. 

 

After the battle with Muzan, Yushiro was living on his own in his and Lady Tamyao’s old home. It was… Lonely, to say the least. His heart ached for the woman he cherished above all else, even himself. But, he was a demon, and he outlived all. As Japan began to boom in population and technological advancements increased, he was forced to move constantly in fear of his discovery. Thankfully, the Ubuyashiki kid gave him way too much money for someone living on their own. It was the son, he thinks. What was his name again... Kiriya? Yeah, that sounded right. 

 

Eventually humans with powers began to pop up around the world. The government called them “metahumans”, Yushiro, at first, thought they were demons. But as time went on and panic died down, he calmed as well. Though he still doesn't trust these metas, one can’t help but wonder. Maybe some of the demonslayer corps were metas? It would explain the inhuman feats they could accomplish. He highly doubted it though. 

 

Soon enough, living in Japan was getting harder and harder. The population continued to skyrocket and everyday was a threat of his discovery. He couldn't keep wasting money and time trying to find a new place to live nearly every month. It didn't help that a woman who lived down the street from him looked identical to…

 

It didn't matter 

 

He saw in a newspaper article, there was a city in the Americas, called the quote on quote, crime center of the world. If Gotham was so riddled with crime, the authorities surely wouldn't notice a demon purposefully slipping through the cracks. So, that's exactly what he did. He booked an overnight flight from Japan to America, then he made his way into the dull city. It would be a lie to say he didn't like the weather. The constant cloudy skies and rain allowed him to go out during the day, only for a few hours covered from head to toe of course. But it was nice. It's been years since he felt comfortable enough to go out on cloudy days anyways. 

 

He got himself a shabby little ground level apartment just on the edge of Park Row. He used a handful of talesmen to keep it looking rundown and abandoned on the outside, but, on the inside, it was clean and well put together. It looked just like his old house, the one he lived in with Lady Tamyao. Of course there were major differences. For example, he only had one bedroom and one bathroom in the building instead of two stories and a basement. But he made due with what he had. 

 

He liked the small house. It was easily maintained. 

 

He stayed in Gotham for a long time, so long in fact, he was able to watch the rise of Batman and all of his Robins. To be honest, he couldn't understand how one man could enjoy being around so many children… All Yushiro had to do was be around the demon corps members and they annoyed him. Especially that Murata guy- what a pain in his side. Yeah, that guy was in his 20’s, but yelling at him to EAT him?? Who does that?! Maybe he was into it… freak…

 

Now it was… whatever year it was, he gave up on keeping track. All he ever did was keep track of how old he and Chachamaru were. Oh, yeah, Chachamaru has been following him around ever since the final battle. Not that he could blame the cat, the last demons alive should stick together. Muzan learned that lesson the hard way. 

 

Yushiro blinked his gaze as the vail filled completely, the already dead man looked even paler than before. He stood as he discarded the needle tip halfheartedly, dusting off his baggy pants and readjusting his rain jacket hood. He looked down with the softest of smiles as the calico cat rubbed against his legs. Yushiro whipped off any residue on the vail before opening Chachamaru’s backpack, placing it inside, and rewarding the cat with a few pets. 

 

That's when he sensed a presence approaching, and quickly, Chachamaru noticed it too as his body stilled and his feline eyes narrowed towards the roof tops. Yushiro swiftly scooped up the cat by the pits before rushing behind a lone garbage bin, his breaths silent and steady. Chachamaru mewed quietly as he looked up at Yushiro within his tight grip. His hind legs wiggled until he could scurry his way onto the demon’s hunched shoulders. Yushiro’s pupils thinned into sharp slits as he watched the white and blue aura move from rooftops to the alley floor. Good, he hid just in time. As his eyes returned to normal he realized it was a Robin, the newest one more specifically. The kid was examining the dead body just a few feet away, he could see the white eyes of the domino mask narrowing as he thought. Yushiro was acutely aware of the boy's glare shifting from the bloodied head, to the cat bite on the body's leg, and then to the fresh puncture wound in the crook of the man's arm. 

 

Robin took a quick swab of the man's blood before bagging it and putting it into who knows where. His breathing hitched sharply as the kid turned towards him, his gaze landing onto the garbage bin he was hiding behind. He carefully leaned away from the edge of the bin, putting his back to the cold metal. 

 

He heard the sound of wet boots softly picking their way towards him before the figure of Robin completely missed his hiding spot… 

 

If it wasn't for Chachamaru hiding him with the talisman, he would surely have been spotted. He's seen these Bats and Birds grow and learn. They're too skilled to miss a man hiding behind a garbage bin of all things. Chachamaru purred lightly, releasing the talisman’s power with a soft meow before laying down on top of Yushiro. The demon stood, glancing around with careful gaze before swiftly retreating the opposite direction Robin disappeared to. 

 

He got the blood, that's all he needed anyways. The last thing he wanted was to be confronted by one of the most violent Robins yet. That's not to say the second one didn't have some violent urges... He could see that boiling beneath the surface. But at least that one kept a smile to his face. 

 

The first one had the same thing, but thankfully he moved to Jump City after he and the Bat split. Now he's known as Nightwing if he could remember correctly. 

 

Don't be shocked that he knows so much, if you had the power to distinguish auras like him, it would be easy to figure out. Especially when Red Hood first appeared, he wonders how long it took before the big Bat finally pieced two and two together. Not to brag, but he knew since Red Hood’s second week in Gotham. Sure, he only knew because of a very minor run in with the brick wall of a man. The whiplash in appearance compared to how the old robin used to look would make anyone stare if they knew! But, that’s besides the point.

 

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Damian POV 

 

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Damian had been patrolling when he heard movement in a nearby alley, with his curiosity piqued, he went to investigate. He landed silently against the wet pavement, the sounds of rain muffled by the brick walls on either side of him. He did not need to search very hard before spotting a deceased man, his face mangled beyond recognition. Gang violence was his guess. As he moved closer, he spotted something odd, a cat bite was taken out of the man's ankle. The poor cat, the thing was probably starving, having to resort to human flesh as a source of food was never ideal. As he thought of what stray could have left the mark, his eyes traced the man's appearance, looking for any more oddities. Like a pointer he perked up when he spotted the subtle mark on the man's inner arm, right where the crook of the elbow would be. A small hole was there, left from a thick needle… Damian would have pushed it aside if it wasn't for how fresh it was. The last drool of blood the man had in his body was dripping from the hole. Someone had either injected a dead corps, which would be a great waste of money and product, or they had taken his blood.

 

Why? Was the question he wanted, needed, answers to. 

 

The person had to be near by, that movement he heard must have been them leaving. Damian lifted a hand to the coms in his ear, keeping his voice low as he reported back to both Oracle and Batman. 

 

“Ive found another body, just north of the one found 2 weeks ago. Same injection mark on the arm. I'm in search of the culprit, they're close. Oracle, send the police to my location for the body's retrieval.” Damian said quietly into his coms, his voice steady and serious as ever. He clicked against the ear piece, muting his mic as he moved quickly down the alley, his hands itching for his katanas. You couldn't blame him, Gotham and the league both taught him to always be aware… You never knew when someone would jump around a corner. 

 

Damian glanced behind the trashcan as he passed it, seeing nothing and kept down the alley way. Though, after a few minutes of searching, he saw no signs of someone on the run. He must have just missed them, that was the only explanation. He reached into his belt and pulled out the compactible, yet strong, grappling hook, shooting it up and pulling himself into the sky. He expertly landed on the roof and made his way back to where he last saw his father. 

 

Batman was waiting where they had parted, Robin swiftly jumping over the gaps between the roofs before stopping beside the older man. Damian looked over the roof's edge, trying to see if he could spot anything below. 

 

“Robin...” Batman spoke gravely and dull as ever. But to the trained ears of the Bat’s son, he could pick up on the friendly greeting hidden underneath. Damian turned towards his father, Robin’s black and yellow cape wrapping around himself. “Father. We need to start looking into these bodies. There's no mistaking it, the pattern keeps showing up. There’s someone testing on or taking things from these dead bodies. We need to figure out-” 

 

He was cut off by a deep huff from the Bat, his lips twitching before he spoke. “No, we have more important things to deal with. Killer crock is still on the loose.” His voice was stern, the barely moving expression on his face revealing his concern. Damien knew his father was right. These were people who died before the mysterious person had stuck them with a needle. For the moment, there was nothing proving they could be dangerous. The vigilantes of Gotham still had rogues terrorizing the streets, they had muggers and bank robbers to stop.  

 

They had much larger problems to deal with than some dead bodies with strange markings. Not to mention these bodies have been showing up for years. Same general area, same wounds, same freshness. 

 

They've been here even before Richard was robin…

 

Damian sighed quietly as he turned away from Batman’s gaze, his brows furrowing beneath his domino mask. “Fine, but I will keep looking into the bodies.” 

 

“Yes… I know.”