Yeah...I had a lot of fun with this one ^_^

It might surprise some people, but Nezu has always enjoyed wandering outside UA and seeing the city.

True, on the grounds of UA he has almost total control and free reign, but there's something truly vindicating about being able to wander throughout humanity and bask in the double takes and reactions. Watch them stare at an animal achieving a dream held by all humans, and is now in control of young human's futures regarding said dream. It's just not worth it if he can't go out and shove it in societies face.

Today, he's meandering in the streets before school, when he reaches a local park and does his own double take at a cat stretching on a bench.

Now, cats are hardly an odd thing to see, but there's no denying that the cat appears to have fire coming out of its ears.

He cannot be blamed for being curious – it's practically his civic duty to investigate.

The cat at least, seems fairly disinterested in it's audience, shifting into a sitting position and watching Nedzu with a bland expression. It's – no wait, she, is a rather fetching creature. Mostly cream with several large spotted patches that remind him of a leopard (some kind of hybrid perhaps?) and huge ruby-red eyes, that match the colour of the flames flickering out of the large ears and around the fluffy paws. Since she's not also writhing in plain, it's safe to say this isn't a case of animal cruelty.

But most mysteriously, the feline has a large stone embedded in her forehead.

If he'd had any doubts before, they're gone now. This animal is one of the extremely rare few to have developed a quirk.

"Well now" he says. "I wonder if its nice to meet you?"

The cat cocks her head, and then stretches it out. Slowly, he reaches out at paw, and tentatively scratches under her chin.

It's probably safe to say the cat's quirk is not intelligence based – although every animal with a quirk is almost always more intelligent than the rest of their species – but where exactly this cat came from is a mystery.

Since animals (outside of him at least) can't be expected to uphold human laws, quirk animals are far more restricted. Already an exceptionally rare thing to see in the first place - you very rarely see them outside of high profile zoos, science labs (though not for long if Nezu gets wind of it), or very rich or influential members of society having them as pets. A quirk-cat certainly shouldn't be wandering the streets alone.

The cat apparently, seems to agree; because when Nezu draws his hand back, the cat shuffles on her feet, and leaps onto his head.

"Ack!" he squawks, flailing and waving his arms as he handled to extra weight. The cat apparently didn't care, padding her paws into his fur before choosing to settle down between his ears.

For a moment, he freezes, eyes flitting around to make absolutely certain nobody had seen that embarrassing little moment, before sighing and heading back.

Well, at least this saves the problem of getting the feline back to UA to check up on her registration…

Twenty minutes later, the cat is happily lapping up some lukewarm tea while Nezu runs a microchip scanner along her neck and back. All quirk animals are required by law to be chipped – although he personally had his removed after a lengthy court case. It's about the only scar he is proud to have.

He can't say he's surprised to find the cat doesn't register. There would have been alerts about a registered animal going missing, so...Hyo, he'll call her Hyo for now, must be unregistered.

Right on time, there's a knock on the door, and both Chiyo and Aizawa walk in.

"Morning Nezu" Chiyo greets, setting a laptop on a low table. "You needed me for somethi-"

"That kitten is on fire" Aizawa gapes, eyes wide, and Nezu frowns.

"Kitten? This is clearly a cat."

Not to his surprise, Aizawa's barely paying attention, idly shaking his head as he approaches the feline. Hyo pops her head up to glance at the man, and happily ducks her head under Aizawa's eager hand.

"She's big, but she's definitely a kitten" Aizawa insists. "Her fur is far too soft, and look at those paws. Hasn't even started growing into them yet."

He grin gets even wider as he sits in a nearby chair, and Hyo jumps into his lap, happy for the attention. "Hey gorgeous, where did you come from?"

Now that Aizawa's pointed it out, the cat's youth is obvious, and Nezu feels himself frown. He can't believe he of all people got swindled by size.

Chiyo on the other hand, just smiles at the scene before glancing over at Nezu, who has grabbed a cup of tea to hide his annoyance.

"Well, I can see why you wanted Aizawa here, but why am I?"

Nezu huffs, but decides that revelation does perhaps clear up one thing.

"I needed your medical expertise" Nezu explains. "This lovely lady-"

He gestures towards the kitten who is happily basking in Aizawa's attention. "Was in one of the local parks without an escort. Given that she's clearly blessed with a quirk, that seemed highly suspect, and I brought her here. I've been calling her Hyo for now."

"Hyo" Aizawa repeats. "That's very fitting, isn't it Hyo? Yes it is, yes it is."

He scratches her forehead, just above the stone, and the cat yowls, shaking his hands off to stretch. Nezu can't blame her – Aizawa using baby talk is in fact one of the most unnerving things he's ever seen. And he's seen a lot.

"Ahh" Chiyo says, nodding in understanding. "She's unregistered. You want to get her microchipped and on the system."

"If you wouldn't mind assisting" Nezu agreed. "And then we can work on finding her owner. I originally thought she might have been the pet of a criminal given the lack of chip, but since Aizawa is probably correct about her age, she might have just recently come into it."

"If she doesn't have one, can we keep her?" Aizawa asks, dragging his eyes away from his prize. "I can make it a class project. Teach them responsibility."

"You'd really let that poor little creature be at the mercy of your class?" Chiyo jokes, and Aizawa frowns.

"Good point."

He lifts Hyo up to his eyes. "We'll get you home, but I promise if they're not suitable, we'll find you a much better one. Does that sound good?."

Hyo just starts writhing, and Aizawa brings her back to his chest, where she immediately digs into his scarf to settle. The grin on the hero's face is a whole new level of creepy.

"Okay then, let's get started" Nezu says, walking to his desk and pulling out the chip gun and handing it to Chiyo.

"You couldn't have done this yourself?" Chiyo asks, activating the device while Aizawa coaxed the kitten into his arms. "I know you know how to do it. You just need medical personnel for the registration."

"Despite what Sunday morning cartoons will tell you, I don't take enjoyment in tormenting cats" Nezu offers with a smile. Chiyo huffs.

"You mean, if she takes offence at the microscopic iota of pain she might feel, you want her angry at the humans instead of you?" she translates. Nezu just grins and picks up his tea cup again.

Hyo struggles a bit in the hold as Chiyo approaches, but with practised ease, the woman slips in and places the gun at the cats neck.

"Here we go."

"MRAOW!"

Hyo immediately starts hissing and clawing up Aizawa's chest. The hero happily lets her dig back into his scarf while Chiyo hands the device back to Nezu.

"Okay, that's her chipped, let's get her registered" she says, sitting down and opening up the laptop. "I'm guessing we'll be relatively vague until she's thoroughly tested? Unless you recognise the breed Aizawa."

The man frowns, though one hand is deep in his scarf where the Hyo is hiding. "Afraid not. Pretty sure she's probably a cross-breed. Definitely no pure domestic line; probably some kind of Savannah Cat?"

"We'll go with 'hybrid' until we can test genetics" Chiyo says. "And what do we know about her quirk?"

"Not much I'm afraid" Nezu replies. "I didn't want to test it out in public."

"The fire isn't actually fire" Aizawa notes. "I've been holding her for the past five minutes and nothing's burned. It could be illusionary, or some kind of aura."

"We can certainly test for it" Chiyo agrees. "Now, she's clearly happy where she is, but we do need to make sure the chip is working, so if you could coax her out?"

Hyo is very unhappy to be pried from her nest, and Aizawa looks genuinely distressed to set her down on the table, so Nezu tries to distract her with another cup up tea while Chiyo runs the scanner.

A minute later, all three of them are frowning, because while Chiyo is scanning every inch of the stressed kitten's neck, no chip is being picked up whatsoever.

"Chiyo?"

"It makes no sense" she mutters. "I checked the chip myself. It was brand new."

"Could it have been defective?" Aizawa offers, and Chiyo starts glaring at the scanner.

"It must have been. I'm going to have to have words with the suppliers. Those chips are supposed to handle everything from natural disasters to hero level quirks."

Nezu sighs, and idly scratches one of Hyo's ears.

"Sorry little lady, but I'm afraid you'll have to tolerate us once more."

Unfortunately, Hyo seems to remember what the gun did last time, because she absolutely no interest in complying. They have to physically hold her down to implant the chip this time, and Nezu mentally writes off the table when he gets a look at the impressive claw marks the kitten managed to wedge into the varnish. Which makes it even more frustrating when the scanner still doesn't pick up the chip.

"I don't understand!" Chiyo huffs as she drops the scanner. "Two malfunctioning in a row should be impossible, it must be quirk related. The fire must have some effect on electrical items."

Nezu nods and glances at the fire burning in the cats ears and paws. It's a rather strange side effect, but hardly the weirdest. Although…

"Those flames are significantly lower than they were when we met" he says, leaning down to look at the kitten. In the park, the flames had almost flared out of Hyo's ears, but now, he can barely see them poking out.

"She must have activated her quirk when the chips were implanted" Aizawa theorises. "Perhaps the flames are an indicator of how long it can be activated?"

"In which case, it would be prudent to wait for the flames to go out before attempting another implant" Chiyo states, stepping back and glancing at Aizawa. The hero nods in understanding, and his eyes flash red.

However, rather than vanish, the flames remain where they are, while Hyo cocks her head and reaches out a paw for the flying hair strands. Aizawa immediately deactivates his quirk and frowns.

"No effect."

Nezu starts grinning.

"How fascinating" he says. "Some kind of mutation that appears as an emitter but doesn't follow the same rules? That's exceptionally rare. I don't think any animal has been registered with such a complicated quirk."

"If it can't be deactivated, it's entirely possible the flames will never extinguish" Aizawa warns him. "We might want to consider registration in the form of a collar, at least until we better understand her quirk."

And while Nezu loathes physical tokens of ownership, the lovely Hyo isn't giving them much option.

"Very well" he says. "I'm sure the Support Department can whip up something temporary. I'll go speak to Power Loader."

He glances down at the cat, and waves a stubby finger.

"Now, don't get up to too much trouble while I'm gone" he says. "If you behave, I'll even see if Lunch Rush can whip you up something a little more healthy than tea."

Hyo just yowls, jumping off the table and starting to slink around the chairs. Aizawa is loathe to leave, but Chiyo yanks him out, reminding him that classes will be starting in a matter of minutes, and reminding him that the cat will still be here this afternoon. Nezu follows, stopping as he closes the door to see Hyo jump onto the windowsill, pawing at the glass.

It doesn't stop him from closing and locking the door though – that window pane is locked with a fingerprint lock and reinforced to give anything short of All Might pause. He highly doubts the kitten will succeed.

Which makes everything just that little more embarrassing when he returns 30 minutes later, collar in one hand, steamed chicken in the other, to find a locked office utterly devoid of feline existence.

He checks, thoroughly, just to make sure the cat hasn't just found the perfect hiding spot. But despite the door and window being completely untouched, Hyo is gone.

Is it the traitor they've started to consider existing in UA? Or was this Hyo's still un-recognised quirk?

He moves to his desk, turning on his computer and switching to the security feeds and winding back to the moment he left the office. He sees himself walk out and lock the door, while Hyo paces on the window sill, looking agitated.

Five minutes in, she jumps down and circles the room.

Ten minutes, she jumps onto the chair that she'd shared with Aizawa and curled into a ball.

Thirteen minutes in…

Nezu's eyes widen as the flames he can only just register finally snuff out, leaving just a cream and spotted cat – who an instant second later, vanishes in a puff of red flame. It looks similar to a flash of magicians fire, or that last final second before a candle wick runs out.

He checks the chair again, but to no surprise, he can't even smell the faintest hint of smoke.

Eventually, he settles back down in his chair, and re-watches the feed from the second he brought the mysterious Hyo inside. Despite his frustrations, he can't resist the smile that crawls on his face.

"What a fascinating mystery this is. Who, or what are you, my curious little Hyo?"

The immediate theory put out once the rest of the staff are brought up to the speed, is spy. A theory that is almost immediately snuffed out by the fact that Hyo had done absolutely nothing spy-worthy. Even while locked up in a room with Nezu's computer right in front of her, she'd been more interested in pacing the room and getting attention.

Which leads to Present Mic leaning back in his chair in the staff room after the briefing and musing at the ceiling.

"What if you had it backwards?" he offers to Nezu and Aizawa. "Rather than a cat with a quirk, she was a quirk, that was a cat?"

"Interesting" Nezu offers. "State your case, Mic."

The blond grins and starts hanging of the back of his chair while Aizawa frowns from his slouch.

"Well, the kitten couldn't be tagged, and she vanished in a puff of flame, so maybe she wasn't as real as she looked. What if someone out there has a quirk that allows them to summon a fiery little kitten? Can't chip something that's not real."

Aizawa mumbles into his arms – something along the lines of 'best quirk ever,' but Nezu ignores it, nodding at Mic's analysis.

"It certainly holds water" he admits. "Especially considering Hyo's unique build, and the fact that she's still not been reported missing, or indeed reported at all. It can't hurt to check the quirk database and see if any quirks in the neighbourhood match up."

As it turns out, there was a six year old about 3 miles away whose quirk did involve summoning animals, but he could only summon nearby animals and didn't recognise the photo of Hyo, so they were left at a dead end. After a week, Nezu was starting to think Hyo would remain an unsolved mystery...until he walked past a certain park and found the kitten stretching out on the see saw.

This time around, her flames were already dim, so he hastily lured her back to UA with a copious amount of hastily bought fish, and let her lounge in his lap while he attached the collar as tight as he dared it to go. After the first disappearance, Power Loader had also added a tracking device, and an extra quirk dampener to make sure the thing couldn't be removed too easily.

Hyo clearly didn't like it, immediately scratching at the band, but after a minute, gave up and jumped back onto the windowsill to paw the glass. She glares back at Nezu, who merely pours himself a cup of tea.

"Ready to leave so soon Hyo?" he asks. "We're just getting to know each other?"

Like before, the cat jumps down and prowls the room, before choosing the comfiest seat to lie in. As she had previously, when the flames in her ears finally snuff out, the kitten vanishes in a flash of red flame...and the collar drops to the cushion, devoid of cat, and looking as if someone had thrown it through a wood chipper. The edges almost looked as if they were rotted away.

It reminds Nezu a little of the damage the villain responsible for the USJ attack caused, but a thorough exam of the evidence quickly proves it's superficial. Thankfully – he didn't want to tell Aizawa his new favourite kitty really was a spy. The hero would be gutted.

However, this inability to register the cat is becoming an issue. Perhaps it's time to try a more unconventional approach.

The third time Nezu runs into her, Hyo is found on the UA grounds themselves, making a pretty decent beeline for the office, and happily tucks into a fish while Nezu calls for Aizawa to bring a student to his office.

Five minutes later, the man walks in with Koda Koji, who at the sight of Hyo, has his face light up as if every birthday has come at once. He makes just as much a beeline as Aizawa first did, gaining Hyo's attention with a quick chin scratch as Aizawa explains the situation.

"Your quirk only works on animals, so just finding out if you can understand her will help immensely," he explains.

"We need to know where she keeps going," Nezu adds. "Is she an animal? is she a quirk?, just...whatever you can give us."

'I'll do whatever I can' Koda signs, and focus on the cat in front of him, whose eyes are narrowing. She's learned to suspect people in this room when they start concentrating on her. 'Do you know her name?'

"We've been calling her Hyo," Nezu replies.

Hyo immediately yowls, and Koda nods.

'She says her name is Uri' he signs, and the heroes straighten.

"You can understand her?" Aizawa asks.

"So she is an actual animal" Nezu summaries. "That's one mystery down."

And a million more added.

"How long have you had a quirk Uri?" Koda asks, and when Hyo – Uri, Nezu corrects himself, yowls again, Koda moves closer.

"Oh..." he says. "Um...a quirk is...Oh it's a special power than only you have? Like your fire. How long have you had that?"

This time, the cat offers a long growling purr, and Koda looks puzzled.

"What? I don't-that's...is that possible?"

"Koda?" Aizawa questions, and the boy flinches.

"Oh, um," he stutters, before raising his hands.

'Uri says she doesn't have a quirk' he signs. "She says she's a 'box animal. They're animals that run on...'

He pauses, and they frown.

"Run on what?" Nezu repeats.

Koda frowns.

'I don't...maybe it's a difference in translation. She's using a weird dialect that I haven't heard a cat use before. But I think she's saying...soul fire?'

Aizawa glances up at Nezu, who just shrugs. It's not a term he's ever heard before. Uri is still making that weird growl-purr though, and Koda keeps signing.

'She says her soul fire comes from...this is definitely a translation issue but, from 'AngryYellingStray?' He takes care of her and feeds her soul fire.'

"Angry, yelling, stray?" Aizawa repeats in confusion. Nezu however, vaguely remembers enough of 'before' to make the connection.

"Animals don't necessarily know their master's names" he tells the two. "AngryYellingStray is most likely her way of describing her owner."

"...That's not a very positive description" Aizawa says, face dark. Uri Hisses, and Koda flinches.

'Uri loves AngryYellingStray' he signs. 'He's never hurt her, and she'll claw up TiredSoftScarf if he tries to hurt him."

Aizawa gives a slow blink, and Nezu has to bite down a smile at the description Uri has chosen for her most doting fan.

'AngryYellingStray is just angry at other people,' Koda translates. 'And he mostly yells at...LaughingBladeDogBird and YellingPunch. He was alone until ShriekingTinyLion took him into the pack?'

Nezu barks a laugh.

"Well, I think it's safe to say we wont be getting any names out of this interrogation."

Uri, apparently bored with the conversation, gets to her feet and – after a quick dip under Koda's arm, makes a beeline for the window.

"Stop" Koda orders. "I want to ask a few more questions."

Nezu can feel the quirk echo in the room, and his fur bristles despite it not being aimed at him. To the surprise of all, Uri doesn't even hesitate, jumping for the window and giving them an arrogant glance.

"...Come back here?" Koda offers, with less force than the earlier command, and sinks as it has absolutely no effect. He turns to Aizawa in confusion.

'I don't understand it' he signs. 'I understood her perfectly. It should work.'

"Which adds another layer to this mystery" Nezu agrees, because Koda's quirk is a two way street – he shouldn't be able to communicate with anything that isn't consider an animal, and as such shouldn't be immune to his command.

'I guess while a 'box animal' is considered an animal, because they register as a quirk based life form, they're not under my quirk influence,' Koda signs, and Nezu walks to the window and their now frustrated guest. He grins down at the cat, watching the tail thrash as she paws the window.

"Fascinating" he says. "Our little Uri is quite the conundrum. We'll have to investigate further."

And with that, deactivates the lock and happily pushes the window open, and watches the cat leap from the second storey window.

Aizawa and Koda immediately lunge towards him, reaching Nezu in time to see the cat land and bolt across the grounds with the slightest issue.

"Why did you do that?" Koda wails. "She could have been hurt."

"She's a very intelligent creature" Nezu explains. "I highly doubt she would have jumped if she didn't know she could make the landing."

"Headmaster, you're not worried?" Aizawa asks, as Nezu makes his way back to his chair. "We have an unregistered quirk...box...animal...thing, running wild in the city, with no clue where she came from. Shouldn't we be containing her?"

"And we will be containing her how?" Nezu asks. "Until we learn more, it's best to encourage her to return of her own volition. She does seem to like entering the UA grounds since we've proved she can get food and attention here. As such, I see no need to be overly concerned – she'll return to us, in time."

Yes, allowing this...'box animal' free reign is by far the best option for now, Nezu thinks to himself. While Uri herself doesn't seem interested in causing harm, her existence cannot have been caused naturally – the strange term 'soul fire' lending more creed to that than anything. The more opportunities that arise to bring her to UA, the more chances they will have to discover precisely who AngryYellingStray is.

And possibly lead them to the other box animals. Koda didn't translate 'box cat,' which means there are more than Uri's out there. At least some kind of dog (and or, bird), and a lion, if Uri's description of her owner's colleagues ring true. And if someone is experimenting or creating quirk animals, Nezu has every intention of being on the front lines when they find out exactly where...

Meanwhile, in a restaurant a few blocks away.

"Goddammit Uri! Stop running away when I summon you!"