I do not own BNHA or its characters.

Enjoy Chapter Six of "Catalyst"

Cowritten and proofread by aoimikans on Tumblr.

Little Discoveries

It was a dull itch that pulled Toshinori from his deep sleep. It flared along his spine, tingling and making his back twitch in irritation. Groggily rolling onto his back, he huffed and thumped his tail in discomfort when his spikes pressed into the mattress, keeping him from lying flat. He groaned sleepily as he stretched his legs and, wiggling his shoulders, scratched his spikes against the bed.

"Ah! All Might, you shouldn't do that!" he heard Isamu whisper urgently.

Toshinori stilled and sat up with a grunt. Yawning widely, he reached up and scratched at the back of his neck. He frowned. The muted sensation of the velvet was numbed and the itch only worsened as he scratched.

"All Might," Isamu called softly.

"Hm?" Toshinori blinked sleepily.

The room was lit by the soft light of early morning. A slight chill in the air made Toshinori's hackles raise and goosebumps spread down his arms. He rubbed at his forearms and looked over to Isamu.

The young nurse sat cross-legged on his bed, and an open book rested on his lap. He smiled and raised a finger to his lips, pointing to the side of the retired hero's bed.

Toshinori's ears perked, and he glanced downward. A small smile lit up his face, and he chuckled softly. Recovery Girl sat in her chair at his side, laying her head and arms against the bed in sleep. Toshinori collected his blanket up and gently draped it over her shoulders. He smiled and gave the bed a satisfied tap with his tail as he tucked the blanket corners under her arms.

"How late was she up last night?" Toshinori asked, voice gravelly with sleep.

"She was awake when I dozed off. After midnight," Isamu admitted.

"Of course," Toshinori shook his head fondly, "She has a tendency to worry too much."

Isamu paused, looking curiously between Toshinori and Recovery Girl.

"You seem … close?" he said cautiously, reluctant to pry.

"She's an old friend," Toshinori smiled at Isamu, gently placing a hand on his scarred side, "And she saved my life more than once."

"Oh," Isamu paused, rubbing his neck only to tense and drop his hand into his lap again. A small, sad frown sobered his expression, and he fidgeted, fingers nervously intertwining with each other.

Toshinori's tail curled thoughtfully, tufted end flicking from side to side.

"Are you alright, young man?" he asked.

"I'm… adjusting," Isamu shrugged and tried to grin. It fell short of his eyes.

I understand. Toshinori sighed, a small shiver running down his spine as his sweatshirt rubbed against his growing spikes, Like losing a piece of what makes you you.

A quiet thought stirred at the back of his mind as he looked down at his awkwardly outstretched legs and gently shifting tail.

So what do these make me?

"Um…," Isamu fidgeted, not quite meeting Toshinori's eyes, "How are you feeling?

Toshinori quirked a brow, frowning in confusion. There was an odd hesitancy in the young nurse's voice. He followed Isamu's gaze to the floor. Trails of scratch marks littered the tile, unavoidable remnants of his physical therapy sessions. But…

Shit. Toshinori rubbed his hand down his face, dread coiling under his scars as the realization hit him. It happened again.

"I feel mostly rested but…" He sighed, resigned, his tail coiling loosely around itself, "What did I do last night?"

Isamu bit his lip and hesitated, pulling his legs up to his chest.

"You, um, got up and walked around for a few minutes. Not much more than that. Recovery Girl asked if you were looking for something," the nurse paused, "Do you have any idea what you would look for?"

Toshinori frowned, shame stirring in his chest, "No… I don't really remember anything when I'm not myself."

I'm still me, but that is something… else.

"Not…?" Isamu sent Toshinori a quizzical look, "You're still you, even like that."

Toshinori furrowed his brows, glancing back at Isamu, "What?"

"When you get like that, you're still you. Just… It's like you're sleepwalking and confused. Overwhelmed…" Isamu fidgeted with the blanket across his lap, "Back at Rishi, you only wanted to escape, conscious or not. And you were protective and kind. You… you couldn't really speak or, um, respond to what I was saying when I talked with you, but…" Isamu pursed his lips, "It's hard to describe."

Something clenched in his gut, and the hackles along Toshinori's back rose with horror.

His chest burned.

Tetsumi's blood on his hands - his claws. Pacing on all fours like an animal for hours, days. Never knowing when he lost time…

That damn fog.

Toshinori swallowed roughly, coughing against the heartburn, and shook his head, "That's not me, young man."

It can't be.

Isamu frowned thoughtfully, "I think you recognized me. You did back at Rishi Gen. And I think you still did last night."

Toshinori turned to look again at Isamu.

"You were still struggling and acted like you didn't know where you were." The young nurse looked pensively at his folded hands, "But you were gentle. You let me convince you to go back to sleep."

Not me, whispered that quiet thought, not -

Toshinori furrowed his brows, "Wait… convinced? How? Recovery Girl said I wouldn't answer her."

Isamu shrugged, "I just talked to you. You were looking for something, so I said I'd take over. Then you went back to bed."

"I -" Toshinori scratched at the back of his neck. The itch was getting worse, "I don't remember."

Isamu paused, his pensive expression shifting to concern, "Is your neck bothering you?"

"Itches," Toshinori said, glad for the change of subject. He pulled a claw cap off with his teeth and resumed scratching at the short spikes.

Isamu swung his legs off his bed, "Hey, careful -"

Toshinori's claw scraped against bone. He hissed, wincing at the sensation. It didn't hurt. If anything, it was a relief.

A small hand tugged on Toshinori's arm.

Recovery Girl adjusted her large glasses and pulled Toshinori's hand down, examining the blood dotting his naked claw.

"You two are loud," she mumbled as she wiped the blood away with a handkerchief, "I need you to lie down on your stomach, All Might."

Toshinori shifted, reaching up his hand again to scratch at the itch, "What wrong with -"

Recovery Girl swatted his hand away, "Don't scratch, I need to take a look at your spikes. Now lay down."

Toshinori huffed, slipped off his sweatshirt, and clumsily flipped himself onto his stomach. His tail slid over the back of his legs and swung off the side of the bed, tufted end flicking impatiently.

"Stop pouting," Chiyo scolded, though she couldn't hide the humor in her voice, "Honestly, you're acting like a child."

She turned and gestured for Isamu, "Can you reach my desk and bring me my gloves?"

Isamu perked and nodded eagerly, "Ah, y-yes!"

The young man scrambled over his bed, still careful to not strain his healing wound, and nabbed the box of gloves. He slid off his bed and crossed over to Recovery Girl's side.

"Here," he held out the box to her.

"Thank you, Nurse Sato," Chiyo said, "Put on a pair of gloves and take a look at this for me."

Toshinori smiled and suppressed a laugh as Isamu froze.

"Y-you want -?" the young nurse stuttered, still holding the glove box.

Smiling kindly, Recovery Girl pushed her chair to the side and gestured to Toshinori's back, "I want your expert opinion."

Isamu was silent, the surprise on his face quickly shifting to determination as he slipped on a couple latex gloves and nodded. His hands hovered over Toshinori's back, and he swallowed.

Toshinori's tail swung contently, brushing up against Isamu's leg and giving him a small, encouraging nudge.

"O-okay, um, let me see," Isamu shifted, flashing a hesitant smile toward Toshinori, and brushed back the hair hiding the smaller spikes.

Toshinori felt the young nurse examine each small spike on his neck, fingertips ghosting over the velvet.

"I'm going to check how sturdy they are, okay?" Isamu says, pinching the first one and giving it a small wiggle, then the second. He laughed, a little nervously, "My third one always tends, um, tended to be a little… loose."

The third spike just barely shifted under Isamu's fingertips.

Toshinori turned his head, glancing up at Isamu.

It really is his quirk…

"Young man?" he asked. His tail wound around Isamu's ankle and gave him a comforting squeeze.

Isamu blinked rapidly and cleared his throat.

"Ah," he choked out, brows furrowed pensively, "It's just… My dad has the same problem, and I got it from him. You'll, um, need to keep an eye on this one. It tends to fall out really early if you aren't careful."

"I may need some instructions, but I'll take care of it," Toshinori promised, reaching back and giving the young man's wrist a small pat, "Are you alright?"

Isamu swallowed roughly and nodded, "Still just adjusting. H-how's the itch? Just on your neck or further down?"

Toshinori paused, gaze lingering on Isamu before resting his chin back on his folded arms, "Neck is worse, and the ones on my back are catching up."

Isamu gently pushed aside the hair along Toshinori's spine, checking each spike and brushing his fingertips over the velvet.

Toshinori shifted as the itch worsened, ears and tail twitching as the urge to scratch at the spikes rose.

"Yeah, you're nearly ready to shed the velvet," Isamu said, "Can you feel this?"

Toshinori cringed, and his hackles bristled as Isamu ran his finger across the spikes.

"Yes. Itches," he said, padded toes curling and tail sweeping across the bed.

Isamu nodded and turned to Recovery Girl, "The spikes are not quite done growing yet. The velvet helps keep them healthy while they finish up," He rubbed at his own neck and shuddered, "Sorry to say, but there's not much we can do about the itch. I had to take a sick day last year and wait it out."

Toshinori groaned as his bristling hackles did little to ease the tension along his back. His fingers twitched, and he grunted, pressing his hand into the mattress.

"I suppose scratching would not be the best idea then," Toshinori muttered, glancing at his claws.

Isamu laughed and patted Toshinori's hand, "Nope. Though an oatmeal bath can help temporarily."

Toshinori inhaled sharply and clenched his teeth as a shiver ran up his spine. He managed a wry smile.

"I think I'll try that bath now."

The halls of the main building were deserted and quiet. There were a couple hours yet before classes began, which was plenty of time to soak in a warm bath. Toshinori pushed his walker through the bathroom door, letting it shut behind -

"Shit!" He jolted, hackles bristling, as a dull, bruising pain raced up his spine. He yanked his tail through the door, shooting an annoyed glare at it and rubbing the sore spot where his tail had been shut in the doorway. Pain receding, he swallowed down the soft growl in his throat and let the long limb swing back behind him, tufted end fluffed and flicking back and forth irritably.

The bathroom was how he left it. Five showers to the left and three large baths to the right. Toshinori caught his reflection in the mirror across the room. It was still… strange. His body shape was all wrong, bent and stretched. A willowy contortion of his true form, and a far cry from the reliable, powerful image of his hero form.

His eyes, two glowing spots of blue in the dark, reflected the low light shining under the door.

Toshinori sighed and turned from the mirror.

He set his towel and the medicated bath powder beside the middle tub and twisted the spigot knobs until warm water flowed steadily into the wide basin.

"Alright," Toshinori grunted and pushed himself up to stand again. His legs felt steady beneath him, barely wavering as he turned from the bath. He glanced at the walker, still standing by the bathroom door.

I can manage without it, Toshinori figured, crossing to the showers.

He stripped off his clothes, fumbling a bit with the buttons above the base of his tail, folded, and set them aside, shivering briefly at the chill on his bare skin. Laying out a small towel and sitting on the bench, he unhooked the shower handle and turned on the water. Not waiting for it to warm, Toshinori ducked his head under the stream. The sudden rush of cold water soaking his hair refreshed him. His ears perked up and alert as he ran his fingers through his wet hair.

The water slowly warmed, and Toshinori sprayed the rest of himself down. He groaned, shoulders relaxing, as the warm water soothed his aches and the itch plaguing his spikes.

Cautiously, he swung his tail under the stream. The feeling of the water was still foreign, but no longer overwhelming. It felt… nice.

Toshinori sighed and grabbed the Heads and Tails shampoo. He massaged the lather through his hair, down the stripe on his back, keeping his claws away from the spiked portion, and along the length of his tail. The tufted end flicked water up, splashing his face.

Cut that out. Toshinori scrunched his nose and snagged the tuft out of midair, giving it an accusatory glare before rubbing soap through the blonde locks and rising it out.

He dropped it, curled his tail over his lap, and finished rinsing. A small purple bruise marked the side of his tail where the door had closed on it. Turning off the water, Toshinori ran capped claws over the mark. Beside the new bruise were the faint remnants of his shackles.

Toshinori laid his wrists beside the scarred ring, both bearing similar marks. His brows furrowed.

Don't let it get to you. It's over. He brushed his sopping hair out of his face, ears flicking droplets off their tips. He quickly pressed his hands over them. They twitched against his palms.

Stop - Oh fine.

Toshinori lowered his hands and grimaced as his ears flicked off the rest of the water. When they stilled, he sighed in relief and stood. Groaning, he pressed his knuckles to his lower back and arched his spine until it popped.

His hackles bristled and the itch on his spikes returned with a fury.

"Bath," Toshinori grunted, rolling his shoulders and gritting his teeth as his claws twitched.

He quickly crossed to his bath, nearly slipping on the wet tiles. The large bath was not quite full when he turned off the water. Warmth wafted from the surface as he sprinkled and stirred in the powder Recovery Girl had given him.

The itch flared again and Toshinori hastily slipped into the bath, water sloshing up and nearly spilling over the sides. He sighed and stretched out, clawed toes peeking out of the water before bumping the far corner, and sunk deeper against the side of the tub. Slowly, the water calmed. The gentle drips from the faucet and the swish of water as his tail swayed just under the surface echoed in the otherwise quiet room.

Curiously, Toshinori glanced over his shoulder, huffing when he couldn't see his spikes. He pushed himself to sit up and twisted, straining to see.

Toshinori hummed and frowned thoughtfully, eyeing the spikes protruding from his mid-back, far more pronounced with the ridge of hair lying flat and wet on his skin. Reaching around, he brushed the back of his fingers along the velvet covered bones. The velvet shifted loosely under his touch and he shuddered at the odd sensation.

"Different," He reminded himself and closed his eyes, "Just different."

Not mine, not right, still whispered a small, panicked voice.

Toshinori shook his head and leaned back into the water. Laying his head back, he traced the swirling patterns of the ceiling tiles with his gaze.

The itch along his spine subsided, and his mind slowly quieted.

Toshinori hooked his arm over the side of the tub, gaze drifting down its length. He frowned and turned his hand over. Small bruises dotted his knuckles where he accidentally knocked them against walls and bed railings. The added length of his arms - only a few centimeters at most, surely - made maneuvering around the infirmary considerably more … difficult. Frowning, he pulled his arm back into the water and sunk lower, stopping with his nose barely above the surface. He sighed, blowing small bubbles and sending ripples across the water, and stretched out his legs.

Toshinori's ears perked and gaze fixed on his toes, What?

He sat up, lifted his feet, and splayed his toes against the wall.

They were partially webbed.

He'd never noticed…

"What else is new?" he scoffed. He let his feet slide back into the water and head thunk against the side of the tub. Laughing softly, exhausted, he rubbed the heel of his palm against his forehead, What else don't I know?

Unease burned and coiled tighter in his gut.

The bath grew cold.

Detective Naomasa Tsukauchi rubbed his eyes tiredly and turned to his cat-faced subordinate, "Who's next?"

Sansa's ears swivelled forward, and he glanced up from a stack of papers. Leaning back in his chair, he tapped the name printed next to a small image on the topmost page.

"Ken Sarubami, registered nurse of thirteen years. Specialization in pediatrics. No criminal history," he answered, "He's the last one for today."

Naomasa sighed with relief and took a long drink from his cup of cheap coffee. He finished it off, grimacing at the grounds at the bottom. Instant. He made a mental note to ask the quartermaster to order a better brand for the break room.

Exiting out of his quickly growing note file, he set his empty mug aside and stood, "Alright. Sansa, you can take the lead during questioning."

Naomasa pushed his chair neatly under his desk, not missing the excited glint in Sansa's eyes. He grinned, "I'll let you know when I get a baseline."

Sansa returned his grin, "Yes sir!"

The station was abuzz with activity. Groups of small-time crooks sat shackled to the chairs lining the front wall, waiting to be processed. A couple battered heroes helped detain a large, unruly criminal, his broad arms bound tightly behind his back by the elastic body of one of the heroes. Tired officers, working overtime and long shifts, hunched over their desks and filing the mountains of paperwork. The uptick in crime was hard on everyone.

Naomasa and Sansa passed through the center of the chaos as they made their way toward the quieter corners of the building and the interrogation rooms.

Ken Sarubami waited in the last room. He sat up straighter when Detective Tsukauchi entered.

"Good afternoon," Naomasa greeted him, sitting down with his notepad and allowing Sansa to take the seat directly opposite the large man, "Sorry to keep you waiting."

"Not a problem," Sarubami said, flashing his impressive fangs with a smile - though it didn't quite match his uneasy tone, "Happy to help."

There was a beat of silence, then Officer Tamakawa smiled amiably, a small trill rolling from his throat as he nodded to Sarubami.

"We're very grateful for your assistance," he said, "Let's start with some easy questions. Ah, and this session will be recorded. Is that alright?"

The nurse glanced curiously to the camera in the corner of the room and shrugged, "Sure. I don't see why not."

Naomasa activated his quirk. Enhanced Perception, it had been labeled. No detail, no microexpression, no vocal shift went unnoticed. Careful training honed the ability and made it a near-perfect lie detector. To his amusement, many of Naomasa's peers claimed his uncanny gut feelings were somehow part of his quirk.

"Firstly," Officer Tamakawa began, "You have been working at Rishi General for seven years, correct?"

"Yes," Sarubami answered, laying his large forearms on the table and intertwining his fingers, "Jedha before that."

Sansa jotted a note of that and continued, "And you work in pediatrics?"

Sarubami glanced curiously at Naomasa who remained silent, and then he nodded to Sansa, "Yes. I usually work with younger children and infants. They're great - well, most of them. Some of them can be real handfuls," he joked, lifting his large hands.

Naomasa had his baseline. He tapped his pen on his notebook three times, signalling Sansa. The only indication Sansa heard and understood was the twitch of his ear and whiskers.

Sarubami shifted in his seat, leaning forward and glancing between the detective and officer, "Can I ask what this is all about? I haven't heard any reason why my coworkers and I are being questioned. Is it about the commotion by the storage building?"

Sansa glanced to Naomasa, deferring the question to him.

Naomasa folded his hands over his notes, brows furrowed slightly. It was his decision whether or not to share details of the ongoing investigation and, more importantly, which details to share.

"A man who went missing last month was held captive in that storage facility. We are just looking for any information you might have, anything that might have stood out to you. People not being where they ought to be. Anyone unfamiliar."

Sarubami pursed his lips in thought, but shook his head. His posture remained open, his expression puzzled, but honest.

Naomasa paused, carefully preparing to gauge the man's next reaction, "How well do you know Tetsumi Inoshita?"

Sarubami groaned, rolling his eyes, "Awful with kids."

Naomasa blinked in surprise. That certainly wasn't the reaction he had expected, "I'm sorry?"

The nurse huffed and shrugged.

"She usually works with long term patients and elderly, but on occasion she fills a vacancy in pediatrics," Sarubami's lip curled with distaste, fangs beared, "She's too scary for kids. Doesn't know the first thing about caring for them. Medically, sure. She knows her stuff, but damn she can't calm a toddler to save her life."

The nurse pointed his finger at the both of them, brows raising, "Kids are pretty good judges of character, you know."

Sarubami caught himself and laid his hand back on the table, "But that's not what you're asking… is it?"

"No," Naomasa said, "She was found in the room where the missing man was held. We have significant evidence she was involved in keeping him prisoner."

Sarubami sighed, "Honestly, that wouldn't shock me. Sorry to say I wouldn't know why though. That woman's always been wound up tighter than the bun she wore. Glad we didn't cross paths much."

Naomasa nodded. There wasn't a lick of dishonesty in the nurse's tone. He wore his feelings on his sleeve, a refreshingly easy man to read. Naomasa flipped through his notes and gestured for Sansa to continue.

Officer Tamakawa straightened and asked, "Have you noticed any of your coworkers acting strangely within the past three weeks? Any working later than usual, or taking time off unexpectedly?"

"Not that I can think…" Sarubami's expression darkened, and he quieted.

"Sir?" Sansa asked after a moment.

Sarubami shook his head, "There's … There's one, but he's a good kid. He's not the type to get mixed up in anything. Always on the straight and narrow, great with kids, a bit shy, but really a good nurse."

Naomasa's detective mask remained impassive, but a spark of humor stirred behind it.

"Would you, perhaps, be referring to Isamu Sato?" he asked.

Sarubami's expression fell, "Damn, he's not involved in your case, is he?"

"Unfortunately yes, but he is in no trouble with us," Naomasa said amicably, not missing the relief on the nurse's face, "Anyone else?"

Sarubami hummed and rubbed at his chin, "That's all I can think of at the moment. Naturally, my main focus is on the kids, not my coworkers.

"If you really want a better idea about where people are and what they're doing, Ayumi Shiire is your girl," Sarubami laughed and shook his head, "I'm not saying she's a gossip, but she handles supply distribution and has a memory like an elephant. So, if you're looking for strange movements, she'd be the one to know."

Naomasa clicked his pen and folded his hands on the table, signaling the end of the interview. No need to continue this one.

Sansa nodded, jotting down a few more notes, "Thank you," Reaching into his breast pocket, he pulled out a card and handed it to the nurse, "If you think of anything else later on, here's our number. We appreciate your cooperation."

Naomasa returned to his desk. The station was still bustling with activity even as the day wore on. He gave passing greetings to those working nearby and sat in his chair with a sigh. Setting aside his notes, he reopened the digital case file and began transcribing his thoughts.

Halfway through a thought, his phone lit up and buzzed beside his keyboard. Naomasa glanced down. It was a text from an unfamiliar number.

[This is Toshinori.] The text read, [The heroics faculty pitched in and got me a new phone. Too kind of them.]

Naomasa smiled, his exhaustion rapidly evaporating. Toshinori usually had that effect on him.

His phone buzzed again.

[How are you? Any news?]

Naomasa saved his document and lifted his phone.

[Good to hear from you. I'm well.] He typed his reply, [Nearly finished speaking with Rishi's staff. We have a few suspected All for One loyalists, but the case is still young. How are you feeling?]

[…]

There was a long pause.

[I have no doubt there are more loyalists at Rishi beside Tetsumi Inoshita. There was at least one other name I heard while there, but I'm sorry to say I don't remember it. A woman's name, I think. On a related note, Isamu Sato is awake and recovering well. I am sure he would be valuable to your case.]

Another pause.

[I won't lie, my recovery is proving frustrating, but it is steady for the most part. Chiyo is making me use my old walker. I will admit that it has made walking easier, but don't tell her I said that. I'll never hear the end of it.]

Naomasa snorted a laugh, attracting a couple odd looks. He raised his hand in apology and glanced back at the screen.

A new text appeared.

[I lost more time.] It read, [It isn't as long as when I was at Rishi, but it is still significant. It's happening while I sleep now.]

The humor drained from Naomasa, and he bowed his head over the phone.

[I'm sorry] he replied, grip tightening on his phone. Guilt stirred in his chest.

If I had just driven you home…

He pinched the bridge of his nose and pressed at his eyes before continuing, [Is there anything you need?]

There was another, longer pause.

[No, don't be, please. It's alright. Recovery Girl will be performing one last check up before I return to the dorms. I think the familiar setting and more rest is what I need. And it seems as long as the door is closed, I don't wander off.]

Naomasa's heart dropped. The idea of Toshinori disappearing again, wandering off in that state, lost - it sent a harsh twist of nausea into his gut. Guilt burrowed deeper still in Naomasa's chest.

I didn't even think about that… Fuck…

His phone buzzed with a following text.

[Found out my toes are webbed. That's new! It feels like there is no end to these little discoveries. I should try seeing if they are good for swimming. Hahaha] Toshinori finished off the text with a grinning All Might emoji.

A small, sad smile pulled at Naomasa's lips, and he scrubbed a hand through his short hair.

Only Toshinori… he shook his head.

[Are you sure you're alright?] Naomasa asked. He knew Toshinori too well to not know when he was hurting.

[I will be] was Toshinori's hesitant reply.

Naomasa frowned and sighed, But you aren't now…

He typed, [If you need anything, don't hesitate to ask, Toshinori. I'm not far.]

Toshinori sent a smiling face with a thumbs up, [I know, Naomasa. Thank you]

"Sir?" Sansa's voice pulled Naomasa from his conversation. He glanced up, spotting the feline officer walking toward his desk. Following behind him was a tall foreigner.

Naomasa gave Sansa a questioning look before standing.

"This man is here to see-" Sansa began but was interrupted when the foreigner strode forward.

"Ah, Detective Tsukauchi, I presume?" He asked, his voice accented. Green eyes raked across Naomasa's face, "I've been told you're the man to speak to regarding the Rishi General Hospital investigation." The man offered a business card in greeting, "My name is William Howard Wright. I'm with an international investigative team in search of a villain we've traced to Japan."

Naomasa's brows furrowed curiously as he took the man's card. He didn't need his quirk to note the man's stiff shoulders and the slight downward cant of his lips.

He's aggravated about something… Naomasa looked past Wright and made eye contact with Sansa, who shrugged. He opened his mouth to speak, but Wright continued.

"Much of our investigation is classified, naturally, but it just so happened that your department stumbled upon a location we've been canvassing for months." The smile on the man's face was tight.

Canvassing for m- ? Naomasa stiffened, a cold grip seizing his lungs. No…

"Perhaps our teams can assist each-"

"Wait," Naomasa held up a hand, ordering his thoughts, "Wait. One: you'll have to get approval from the Chief to step in on the Rishi Gen investigation, and two: you've been watching for months? Did you not notice suspicious activity around the storage facilities? Nothing was called in."

No, Naomasa immediately reasoned, They couldn't have known. If they did, Toshinori wouldn't have -

"Of course we noticed," Wright bristled, brushing his hand over his slicked back hair, "I cannot divulge the details as of yet, or how it may or may not be related to your case, but we wouldn't be here if there wasn't suspicious activity. As for anything specific, a call to local authorities would have jeopardized our investigation. I'm sure you understand."

An odd, disconnected feeling of disbelief hovered sickeningly in the air.

Understand!?

"So," Naomasa grit his teeth and spoke slowly, deliberately, "You knew someone- something was going on in there… and you sat on that information."

Sansa's eyes widened. He looked back and forth between Naomasa and the foreign investigator, hands raised in preparation to diffuse the crackling tension between them. The bell around his neck tinkled softly as he stepped forward.

"There were many suspicious things occurring at that hospital," Wright stated, his tone curiously neutral, "It was why my team and I are looking into it."

Naomasa shook his head and let out a deep breath.

I'm jumping to conclusions. It's a misunderstanding. Perhaps a mistranslation. Naomasa reasoned again, They couldn't know what was happening to Toshinori. They couldn't…

Naomasa bowed stiffly, "I'm sure the task force assigned to this case will appreciate your timely assistance. Fair warning, the head investigator does not appreciate late reports in the slightest."

"Of course, Detective," Wright nodded matter-of-factly, "And who, may I ask, is the head investigator?"

Naomasa frowned at the blond man, phone clutched tightly in his fist.

"That would be me."

Toshinori pocketed his phone and hooked his thumb in his hoodie pocket. He stood beside the window, sneaking a peek down at the training fields. The third years were practicing rescue drills and CPR. He recognized a few he had seen in the halls and lunch room. Fine, young heroes in training.

Toshinori's walker sat beside him, untouched but just within reach. He shifted his weight, claws clicking against the floor and tail swaying. Absently, he rubbed at his abdomen, wincing with a soft grunt at the uncomfortable burning sensation the pressure brought.

"All Might," there was a soft click as the infirmary door shut. Recovery Girl rounded his bed and gestured for him with a smile, "Ready to get that velvet off?"

"Yes," Toshinori chuckled, resisting the urge to scratch at his spikes, and crossed over to the bed, "The sooner, the better."

Isamu sat up on his own bed, a nervous glint in his eyes.

"It won't hurt," he assured for possibly the third time as Toshinori sat, removed his hoodie, and moved to lay on his stomach, "It feels weird and, um, there will be some blood, but it's supposed to do that."

Toshinori grinned and nodded, "It'll be alright."

Isamu opened his mouth to reply but paused and shook his head, pouting a little, "That's what I was trying to say."

Toshinori barked a laugh, coughing when the burning sensation twisted in his gut. He waved away Isamu's concerned look.

"Tell me," he said, clearing his throat, "Does the itching stop when the velvet's off?"

"Oh, um," Isamu nodded, "Yes, it does."

"That's good," Toshinori grunted, laying his head on his crossed arms.

Recovery Girl put on her gloves and pulled a rolling metal table closer, double checking the tools lying on its surface. Toshinori felt her brush aside the hair along his spine and wrinkled his nose as she spread rubbing alcohol along the spikes.

"I am going to start at C1," Chiyo said, tapping the topmost spike on Toshinori's neck, "and work down. Isamu - ah, apologies - Nurse Sato?"

Isamu jolted, "Oh, um, you can call me 'Isamu' if you'd like."

Recovery Girl smiled softly, "Alright Isamu, dear. Do you have anything to add?"

Blushing furiously, Isamu rubbed at the back of his neck and turned towards Toshinori, "I just have some tips for the spikes. You'll want to brush them everyday and polish them once a week. It keeps debris from collecting on the bases, and polishing helps prevent them from getting cracked - from normal wear and tear anyway. They'll be sharp at first, but will wear down throughout the year, so just be careful about bumping into things behind you."

Toshinori nodded.

"Hold still, dear. I'm starting," Recovery Girl said, tapping the back of his head.

Isamu was right. Removing the velvet felt odd. Recovery Girl carefully cut away the loose velvet at the bases and peeled it away, depositing it in a metallic bin for biowaste. Once velvet-free, she cleaned each spike. The absence of the velvet's warm protection felt strange. The alcohol stung the bases and the cold seeped into the spikes like ice water would chill his teeth.

"Done," Recovery Girl slipped off her gloves and patted Toshinori's back, "The spikes on your neck are still about 3.5 centimeters, but the longest five grew since the last check. T1 through T5 are now around 10 centimeters long."

Toshinori shifted onto his elbows, looking over his shoulders, and grunted with frustration.

Recovery Girl chuckled and turned to the metal tray, "Here."

Toshinori grinned at the mirror in her hand, "Thanks, Chiyo."

He took the mirror, adjusting it until he could see.

Huh…

The spikes were cream colored, though they were tinted red with the blood from the shed velvet. Their tips were white and sharp.

"I think I'm going to have to have my shirts adjusted," Toshinori muttered, reaching back and running his palm over the sharp points.

Isamu perked up, "I know a place that is good with my family's spikes. I can give you the address, if you want it."

"Thank you," Toshinori grinned, sitting up, "I'll need a good ta-" A burning ache twisted Toshinori's gut, and he coughed roughly.

"Ugh. Heartburn again," he pain worsened and climbed up his throat. Toshinori stifled the coughing fit, swallowing roughly and wincing at the burning in his chest. He rubbed at his bare abdomen -

His palm brushed over a small lump.

Toshinori's brows rose, "Recovery Girl? There may be something wrong," He quickly raised his hands defensively, "I promise I haven't strained myself, but did any of TB-2's scans show a hernia?"

"Hm? No, no," Chiyo patted his knee as she looked up from the lump, "I have an idea of what it is. Isamu, dear, if you would pass me the manilla folder just there on my desk," she gestured to it before turning back to Toshinori, "Sit back, please."

Glancing between Recovery Girl and the folder Isamu passed across to her, Toshinori sat back against his pillows.

A popping, tearing sound split the air. Toshinori tensed and sat back up. The pillow followed, impaled and stuck to his spikes.

He caught Recovery Girl looking at the torn pillow and mumbled an apology.

"Don't worry about it, All Might," Chiyo said with a smile and lightly nudged him back. She opened the folder, flipped through a few pages, and pulled out one. She handed it to Toshinori.

It was a scan of his abdomen, the shapes of his organs - so many mangled and nearly unrecognizable under old scar tissue - shown in dark blotches.

Recovery Girl pointed to the center of his scanned abdomen next to where his stomach had been, "Look here."

Toshinori furrowed his brows and did as she said, mentally listing his remaining organs: Liver, gallbladder, small and large intestines, part of his pancreas … and a fist sized organ he didn't recognize.

"That," Recovery Girl tapped the image of the strange organ, "is likely what is causing your discomfort."

Toshinori cautiously rubbed at his abdomen, staring at the odd organ printed on the page, "What is it?"

Recovery Girl hummed thoughtfully, "Well, it looks to be an extension of your gallbladder. It's most likely a part of that Devour quirk. If you'll let me take a look, I could give you a better idea of what it does."

Nodding numbly, Toshinori set the scan aside. Recovery Girl pulled her chair closer and felt around the small lump. She gently pressed down on it.

"Hhrk!" Toshinori shot up and coughed into his hand. The force of the coughing fit pressed against the strange burning in his core and choked him. Something hot hit his palm and dripped onto his pants. Toshinori took shuddering breaths as the fit calmed.

"Slow breaths, that's it," Recovery Girl said softly, nudging the pillow off his spikes and rubbing circles on his back.

Toshinori nodded, grimacing at the leftover burning sensation in his chest. Small tendrils of acrid smoke rose from his thigh. He frowned and picked at the holes burned through the fabric of his sweatpants.

"A little warning -" Toshinori coughed roughly, sticking his tongue out with distaste, "That's gross. A little warning would have been nice."

Recovery Girl gave him an apologetic smile, "I'm sorry, dear. Honestly, I wasn't expecting that either."

A tingling sensation pulled Toshinori's attention to his hand. Bile-colored liquid stuck slick to his skin. He wrinkled his nose at the acidic smell and wiped his palm off on his pants, sighing in frustration when the leftover acid began to eat through the fabric. At least the burning in his chest subsided. He glanced back down at his abdomen and gingerly poked at where the lump had been.

Chiyo shooed his hands away, passing him a small towel and paper cup of water. As Toshinori wiped off his hand and thigh, she felt around the area again. She nodded thoughtfully.

"The antacid tablets may have just masked the symptoms, but it looks like you had excess digestive acid stored in what I believe is an acid sac."

Toshinori nearly choked on his water and stared blankly at Recovery Girl, "A what now?"

She pat his abdomen and looked into Toshinori's eyes, "An acid sac, dear. I tried to do some research on the Devour quirk - with mixed results, mind you - and I believe it's part of what allows its quirk user to digest, well, anything really. Normally, the acid would drain into the stomach as needed …"

"But I don't have one," Toshinori finished.

Chiyo nodded, "Resulting in the buildup of acid that needed draining." She eyed his abdomen critically, "For now, I'll give you more antacids, but we'll likely need to consider a way for you to get rid of the excess."

A sense of wrongness twisted Toshinori's insides. He pressed his palm to his forehead and laughed softly, "Anything more I should know about this body?"

Recovery Girl paused, gaze snapping up to examine his face, and she frowned, "Your body, Toshinori."

"Right," he sighed, another half-hearted laugh weakly left him, "My body."

Toshinori hunched forward, closing his eyes. He felt drained. A shiver ran across his skin and he wrapped his tail around himself. The fog -

"All Might?"

At the sound of Isamu's voice, Toshinori looked up and and smiled weakly. He sighed when Isamu's worried frown deepened.

Sorry young man, not my most convincing "brave face."

Drooping ears and a listless tail had given him away, tells he couldn't - didn't know how to control.

Isamu glanced at his interlaced fingers, "It's…" His voice faltered.

The young man paused, searching for the right words. His expression was pained but determined, "It's going to be alright. I-I can't begin to imagine what it's like for you, but you're not alone, and you're still you. All of you. You fought so hard back there, and you won! Don't -," Tears misted in Isamu's eyes, and he swallowed roughly, "You don't have to fight alone anymore. You don't have to bear these changes alone. So… maybe… don't force yourself to."

Toshinori stared wide-eyed at Isamu. The young man didn't meet his gaze, clutching at his shirt above his still healing wound. Isamu, his fellow prisoner, his aid and liberator. He was wrong. Back at Rishi, Toshinori had never fought alone.

Toshinori chuckled softly and rubbed at his eyes, "Thank you."

His… His tail twitched and swept across the bed with renewed energy, the tufted end bristling at the change. Heat rose to his cheeks when he saw Recovery Girl's smile. He grinned and shook his head bashfully.

"Sometimes I need that reminder," Toshinori admitted, "I will be alright. Thanks for looking out for me. Thank you both."

Toshinori stretched out, legs itching to get moving. Closing his eyes, he took a deep breath, "Acid sac. Got it."

He looked up and grinned cheekily, "Can I go home now?"

Recovery Girl chuckled, "Are you sure you wouldn't like to spend more time here?"

"HA!" Toshinori barked out a laugh, "You're not sick of me yet?"

"Well, this is an infirmary," Recovery Girl shot back.

"Fair enough," Toshinori shook his head, smile widening, "I would like to go back now. I think - no - I can manage this."

"Alright then," Recovery Girl said, clapping her hands together, and turned to Isamu, "If you feel up to it, would you help me go over some of these notes? We need to figure out if a change in his diet is in order. For now, I'd say more alkaline foods and branch off from there. Toshinori, I suggest contacting Aizawa first. I'll take care of Nedzu."

Ah, Principal Nedzu. A spark of amusement flashed in Toshinori's chest, and his tail thumped against the bed. He means well, but I think I'll pass on one of his lectures.

"Right," Toshinori pulled out his phone, "You're the best, Chiyo,"he said, giving her a thumbs up.

Recovery Girl gave him an understanding smile and went back to her desk, lifting the school phone perched on it.

Toshinori fished his phone from his pocket and sent his message to Aizawa, [Recovery Girl is discharging me. I am returning to the dorms tonight.] Aizawa would know what to do to prepare their students.

A nervous feeling fluttered in Toshinori's gut as he restlessly pressed his bare feet to the tiled floor.

One step at a time.

Thank you for reading the final chapter of "Catalyst."

We hope you enjoy the next installment of our series: "Control."

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