I do not own BNHA or its characters.

Enjoy Chapter One of "Catalyst"

Cowritten and proofread by aoimikans on Tumblr.

The Return

Five hundred meters.

The fall morning was bright, crisp, and quiet. Wind whipped through Izuku Midoriya's hair, cool but not cold enough to sting his lungs as he picked up speed. His feet pounded against the track and arms pumped at his sides. His muscles burned but nowhere near their limit. Izuku grinned.

Four hundred meters.

The spark in his chest flared, and he activated One for All: Full Cowl. Power darted across his skin and warmed him from the inside out. He felt lighter, the ground softer, the distance shorter, his mind at ease. He ran.

Two hundred meters.

Izuku pushed himself. Seven percent. Eight percent. Nine -

He hissed at the pull at his tendons. One for All fizzled out as he slowed to a jog, then a walk. His legs throbbed, just on the edge of strain. Nothing he couldn't shake off.

Not quite sturdy enough for nine percent yet, Izuku thought with a thoughtful frown. He shook his head, One hundred meters cool down. Then stretch. Maybe tomorrow…

Izuku walked the rest of the loop. The pounding of his heart and breathing slowed as he turned along the last curve toward his belongings. He glanced up and halted midstep.

Someone was sitting in All Might's spot on the bench.

For a moment, he thought -

The person looked up.

"Ah! Midoriya!" Tenya Iida stood, revealing Ochako Uraraka sitting behind him, "Good morning!"

"Morning Deku!" Uraraka echoed, popping up and waving cheerily.

Izuku shook off his surprise and smiled as he jogged toward his friends, "Morning! You guys are up early."

Iida nodded formally, "Yes, well, Lunch Rush is offering instructions on how to safely use the dorm kitchens. As Class President, it is my responsibility to ensure proper use of the dorm facilities."

"And we get to keep and eat whatever we make!" Uraraka exclaimed, pumping her fists in the air excitedly.

"Sounds fun," Izuku said with a small smile.

His friends caught his hesitation and glanced knowingly at each other.

"Are you doing okay, Deku?" Uraraka asked, her voice quiet as she clasped her gloved hands together.

Izuku's smile slipped a little.

I'm making them worry...

He rubbed at his arms and suppressed a shiver. The sweat coating his skin had grown cold. He opened his mouth to reassure them, but Iida suddenly stepped forward and clapped his hands onto Izuku's shoulders.

"The police and our teachers will find All Might. So don't worry, Midoriya!" he exclaimed.

Izuku jumped a little at Iida's volume and blinked rapidly until his words sunk in. He bowed his head a little, pursing his lips, before nodding.

"Yeah," Izuku agreed, rubbing the back of his neck, "I-I know."

"Plus he's All Might!" Uraraka jumped in, smiling brightly. She punched her fist in the air, "Wherever he is, I'm sure he's alright! He's bound to show up soon!"

"Exactly!" Iida crossed his arms and nodded seriously.

Their smiles and faith were infectious, and Izuku grinned.

Uraraka clapped her hands together, "So! You want to join us for Lunch Rush's lesson?"

"Ah," Izuku shuffled his feet and said, "I worked up a sweat out here so I really ought to wash up."

"You can meet us there after that then," Iida suggested, "The lesson isn't for another thirty minutes anyway."

"And if you, um, can't make it, we'll save you some food," Uraraka promised, giving Izuku a small, understanding smile.

"T-thanks," Izuku said quietly.

Iida and Uraraka departed for the dorms with a wave. Izuku rubbed the back of his head and waved. When they turned away, he let his hands drop to his side.

Izuku bit his lip, brows furrowing and shoulders slumping.

All Might...

Aizawa had been the one to tell Class 1A that All Might was missing. None had drawn a possible connection between All Might's disappearance and the escape of the "Kamino Ward Boss," though Kacchan was especially subdued upon hearing the news.

No one knew about Izuku's phone call. They didn't know how All Might sounded…

Dread clenched in his gut. Izuku shut his eyes, shaking away the memory.

"I would appreciate it if you kept All Might's history with All for One between you, Detective Tsukauchi, and myself." Principal Nedzu had said to Izuku. "If you want updates, do not hesitate to come to me."

"Maybe I'll drop in and see …" Izuku mumbled to himself as he picked up his things and headed toward the track-side locker room.

Other than Recovery Girl and Power Loader, the majority of U.A. faculty held office hours in the southeast faculty building. Including Principal Nedzu.

Izuku jogged off the field and toward the southeast corner of campus. His phone buzzed once in his pocket, then again and again. Izuku slowed to a stop and pulled his phone from his jacket pocket.

It was the IFF, "Identification Friend or Foe," app. Izuku's phone buzzed again as another report post popped up.

[anybody know who this is?]

Attached was a picture of … something. It was too blurred with movement to see clearly. A person with a tail quirk, maybe?

The phone buzzed again as two more posts appeared.

[crazy monster by cantina! Somebody send a hero!]

[r you seeing this!1 it's charging thru town! everyone's freaking out!]

There were multiple pictures of the "monster," but none were remotely clear.

Izuku scrolled through images posted in the last half hour, his brows wrinkling in mild frustration. The only focused picture looked like it was taken after the person fell. Clawed hands and feet and what looked like…

Chains? Blood?

Izuku frowned thoughtfully, pinching his lower lip, and mumbled, "Maybe an aesthetic touch? Going for intimidation? Hmm."

Izuku stuffed his phone in his pocket, making a mental note to check in on it after he spoke with Principal Nedzu.

A loud cry split the air and Izuku froze. It almost sounded like a wounded animal, but there was only one thing that sounded like that.

A chill ran down his spine. Noumu…

Izuku looked toward where the sound originated, just on the other side of one of the gymnasiums. His mind raced. Most of the students were in the dorms or visiting family off campus for the weekend. If there were any other students, especially non-Hero Department students, in the area… Izuku's hands curled into fists, determination firing in his core. At the very least, he would locate it and then get a teacher, or hold it off if worst came to worst.

One for All flared to life, shooting down Izuku's limbs. He sprinted toward and around the gymnasium. Rounding the last corner, he got a full view of the courtyard and froze, eyes widening.

Aizawa-sensei!

Aizawa was alone, eyes glowing red and Capturing Weapon extended, holding back the nou-

Izuku's brows furrowed, No… That's not a noumu… Is it?

He was still too far to see clearly, but the intruder's brain wasn't exposed like the noumu at USJ and Hosu. Instead, their head was covered in a shock of blonde hair, partially matted with what looked like dried blood.

Whatever or whoever they were, they were reaching out to -

Izuku tensed. Someone was lying on the ground.

Are they hurt? Izuku moved closer, staying in the shadow of the gymnasium. If he could just get at a good angle, he might be able to help move the victim out of Aizawa's fighting range.

The intruder on the ground twisted up suddenly. Their long tail whipped around Aizawa's weapon and violently yanked it forward.

Aizawa roughly followed, stumbling and readjusting his grip.

The intruder turned and jumped at the injured person on the ground.

Aizawa threw his arms wide, Capturing Weapon zipping around and binding the intruder's legs and tail together. They fell to the ground with a breathless grunt, struggling even when the bindings wrapped around their wrists.

They rolled onto their side.

Izuku's heart dropped.

One for All roared through his veins, and he bolted forward.

"Midoriya! Stay back!" Izuku heard Aizawa shout.

One for All suddenly vanished, erased at Aizawa's glance. Izuku kept running, tears falling behind him.

Izuku skid to a stop and dropped to his knees. His hands shook as they hovered over that familiar scar and the unkempt, blond hair. The bindings cut into the scarred flesh, and horror churned in his gut.

He shouted at Aizawa, voice cracking, "What are you doing to All Might?!"

Aizawa froze, red gaze snapping downward, but his weapon remained wrapped tight around All Might.

Izuku's heart pounded, and tears welled in his eyes as he finally turned to look at All Might.

All Might looked back up at him, panting, clouded eyes wide and mouth parted in shock.

Almost as if…

He's scared. He looks scared. All Might looks scared.

Izuku smiled wide, and tears rolled down his face. One for All ebbed and flowed, stirred by his bubbling emotions, and spilled over. Carefully, he pulled and tore at the binds around All Might's wrists.

"It's alright. It's alright," he whispered. - He's back. He's actually back! - Izuku's smile grew, "All Might. You're here! You're alright!"

With a last tug, the bindings came loose. Aizawa shouted something, but Izuku ignored him. All Might threw his arms around him in an instant, and his face pressed against Izuku's shoulder.

Izuku wrapped his arms around All Might's middle, pulling him up gently. His breath shook and hitched. A small sob escaped him, and he bowed his head over All Might's shoulder. Emotion and relief overflowed and he wept, shoulders heaving and arms shaking. One for All still pulsed across his skin, but he kept his embrace soft.

Something wet bled through Izuku's shirt at his shoulder, and he heard All Might laugh, soft and muffled. Fingers gently ran through his hair, and All Might gave him a small squeeze before pulling away.

"He-" All Might's voice was rough, and he cringed. He pointed to the side.

Izuku tensed, The injured person!

He turned to Aizawa and called out for him.

Aizawa rushed forward, loosening and pulling away his Capture Weapon as he passed, "I've got him."

Izuku watched as Aizawa lifted the stranger. The young man was bandaged and bleeding.

Who -?

All Might suddenly shuddered and pitched to the side, only just catching himself.

"All Might!" Izuku caught his shoulder and quickly gave him a onceover.

All Might's eyes were clouded, his breathing shallow, his arm trembled under his own weight, and the smell of hospital air and spoiled sweat clung to him. Dried blood caked bits of his hair and the short beard on his face. It stuck to his bare skin, though none of it appeared to be his.

It must be the injured person's…

"Midoriya," Aizawa called out, "help him up and follow me."

Izuku quickly nodded to Aizawa and carefully pulled All Might's arm around his shoulder. "It's okay, All Might. Let me help you. We'll get you both to Recovery Girl, okay?"

All Might shivered but managed to nod, shifting as Izuku slowly stood.

"That's it. It's alright. You've got -" Something snaked around Izuku's waist, and he started, looking down. His eyes widened and he stared, "You've got…"

A tail?

It clicked.

Izuku glanced over All Might, who practically hung from his shoulder, finally taking in the rest of his appearance. A long tail, a stripe of thick hair along his spine, digitigrade legs that shook as they walked, sharp claws, pointed ears… Chains swung from thick shackles on each of his limbs.

Izuku's stomach clenched, and he pulled All Might closer. He bit his lip as tears welled in his eyes.

"W-what happened to you?" Izuku whispered.

All Might barely shook his head, "L-long sto..ry. Later…" His squinted eyes were fixed ahead, on Aizawa's back and the person he was holding.

Izuku followed his gaze, "Who is he?"

"... A nur..se." All Might shuddered, squeezing his eyes shut. He stumbled.

Izuku held him up, pausing while All Might got his feet back under him.

" 'm … sorry," he rasped between breaths.

"We're nearly there," Izuku muttered encouragingly, trying to smile, "You're going to be alright, okay?"

All Might hummed, watching his feet as they made their way into the main school building and to Recovery Girl's infirmary.

Aizawa entered the office first.

"Recovery Girl!" Aizawa rushed to the closest bed, laying the injured nurse down flat.

Recovery Girl hopped off her chair and moved quickly to the edge of the bed, examining the nurse and undoing the bloodied bandages around his waist.

"Your field patchwork needs improvement, Eraserhead," Recovery Girl quipped lightly as she discarded the ruined bandages. "Hand me those clean bandages, just in that cabinet there."

Aizawa swiftly retrieved them and the items she listed off. Recovery Girl's hands were nimble as she properly cleaned the nurse's wound.

"Did you roll this young man down a hill before bringing him?" Recovery Girl swatted Aizawa's hand with her cane, "Not to mention there's not nearly enough gauze to hold him together!"

Izuku jumped a little in the doorway when All Might chuckled dryly.

"M-my fault… I'm af..raid, Chiyo."

Recovery Girl blinked and looked up from her work. Her brows rose and wrinkled with worry as she took in All Might's appearance.

"Did … Did my b-best wi..th what I had," All Might smiled at her, though it slipped a little when his left leg gave out.

"I've got you," Izuku mumbled as he shifted his hold.

All Might nodded slightly, shakily pulling himself up. He panted with the effort.

Recovery Girl shook her head, lips pursed, and held her cane in a white knuckled grip.

"Bring him in, boy," she ordered. "Put him on a bed. I'll see to him in a moment."

Izuku nodded hastily. As soon as All Might had his feet back under him, Izuku led him to the second bed in the infirmary. The chains dragged loudly against the floor and rattled with each step.

Recovery Girl shot All Might another focused glance as they passed, shaking her head, and turned back to the injured nurse, "I'll get the details later. Right now, this young man needs more immediate help."

Izuku frowned and nodded in agreement as he stopped by the second bed. All Might sunk down and sat on its edge, sighing and closing his eyes. He slouched forward, elbows resting on his knees and head bowed.

Izuku's expression softened quizzically when the tail wrapped around his waist did not loosen its grip. He carefully sat beside All Might.

Recovery Girl hummed, her expression dark as she examined the cleaned puncture wound. "Oh my… I can help close the wound, but we should really have him transferred to a hospital." She wrapped the clean bandages around the nurse, "I know a great surgeon at Rish-"

"NO!" All Might roared, hackles raised.

Izuku jumped and stared at All Might. He instinctively grabbed All Might's hand, squeezing it the same way his mother would to comfort him. In the corner of his eye, he saw Aizawa's eyes glow a faint red, a hand hovering just by his scarf.

All Might clutched at his forehead and panted. A low growl rumbled in his chest, and he coughed.

"No… Not… not b-back-," All Might shook his head, eyes squeezed shut. He swallowed and the low growl quieted, "H-here. Help him here…"

"Eraserhead," Recovery Girl's lips curled into a determined frown, "call Principal Nedzu at once. I need supplies for abdominal surgery. He'll want to know about this, so fill him in as best as you can."

Aizawa nodded, pulling his phone from his pocket and stepping into the hall.

Izuku leaned closer to All Might's bowed head. Sweat beaded on his forehead, and his whole frame trembled with overexertion from his outburst.

"Is R-," Izuku furrowed his brow, "Is that where you were?"

All Might nodded, sightless eyes fixed on the floor.

Izuku swallowed the immediate thoughts of So close? All this time? Instead his gaze drifted to the shackles around All Might's wrists. All Might absently picked at them and fidgeted with the end of a broken chain.

Izuku grit his teeth, and One for All stirred in his chest at his anger.

"We're getting these off of you," Izuku said, gently taking hold of All Might's hand.

All Might's reaction was painfully slow. He looked from the broken chain links to the injured nurse. His eyes darkened as he shuddered.

"All Might?" Izuku's voice was quiet.

All Might blinked and gave Izuku a tight smile. He flipped his arm over to give him better access.

Izuku smiled back and carefully dug his fingers under the metal on each side of the seam. One for All zipped down his arms and his grip tightened on the metal.

The lock groaned.

Izuku furrowed his brow and pushed a little more power into his fingers.

Eight percent…

The metal creaked but did not break. Izuku pursed his lips and went over his limit. The lock broke with a snap and the shackle fell away and clattered onto the floor.

Izuku flinched as sharp pains darted through his fingers.

All Might grabbed Izuku's wrist, "D-don't hurt you..rself, my boy."

"But-" Izuku curled his throbbing fingers into fists.

All Might admonished Izuku with a look and a small shake of his head. He patted Izuku's fist, claws curling around and giving them a small squeeze, "Thank you… but I ca..n wait."

Recovery Girl looked up from her patient and nodded at All Might's words.

"Allow me."

Izuku jumped and turned.

Aizawa stood by the bed, tucking his phone into his pocket. He fished thin, metal tools from his utility belt.

Lock picks? Izuku thought as Aizawa knelt in front of All Might.

Aizawa pulled the shackle on All Might's leg forward, twisting it until the keyhole was visible. With a few small clicks of the thin tools, the shackle unlocked and fell away.

All Might sighed, stretching his leg and flexing clawed toes.

"Thank you, Aizawa," All Might said softly as his colleague moved to his other leg.

"Don't mention it," Aizawa said flatly.

All Might blinked, a slow look of surprise shifting his expression.

Izuku's brows furrowed.

"Something wrong?"

All Might glanced at him, then shook his head, "Nothing." A small, hopeful smile graced his face as the next shackle fell away.

Recovery Girl tapped her cane on the ground. Izuku glanced up, catching her thoughtful expression as she looked over the injured nurse. With new bandages on and an IV drip in, he looked somewhat better than he had before.

"I've stabilized him for now," Recovery Girl sighed, "but I need those supplies soon. The longer he has to wait, the harder his recovery will be."

Aizawa looked up from the shackle on All Might's wrist, "Principal Nedzu is calling in his connections. I have no doubt they'll be here soon." The shackle opened and Aizawa set it and the attached chain to the side with the rest. He glanced at All Might, "Any more?"

All Might rubbed at his wrists and shifted awkwardly, "On… my tail."

Aizawa nodded, expression serious.

Izuku lifted his arms when he felt the tail around his waist shift and pull away. He watched as All Might turned, hooked his arm around the tail's middle, and pulled it forward.

Aizawa wordlessly bent over the last shackle, picking at the lock.

"Thank you..." All Might said softly. The end of the tail thumped against the side of the bed.

"Hey, if you want this off, you need to hold still," Aizawa griped, though there was no malice in his voice, pushing at the tufted end when it hit his leg.

"Ah.. I don't qu..ite have … control of it yet," All Might admitted, catching the end of it and pulling it to his side, "Apologies."

Aizawa shook his head, and the last shackle opened with a click.

As Aizawa moved away to put the last shackle with the rest, All Might brushed his palms over the red rings left on his tail and his wrists. He closed his eyes, sighing deeply, and a small smile lingered on his face.

Izuku bowed his head, grinning at the sight. He rubbed at his eyes as they misted over and sniffed.

All Might's back. He's going to be okay.

A gentle weight rested on his head, and another heavier one wrapped around his waist. He wiped the last of his tears away and glanced over.

All Might ruffled Izuku's hair. He lifted his other clawed hand and rubbed the heel of his palm against his own eyes, squinting in the light. He looked… exhausted and worn down to the bone, but he smiled warmly.

The smile said it all.

I'm here.

Thank you for reading the first chapter of "Catalyst" the sequel to "Canvas!" Send me a review or PM if you have any questions or comments.