Warnings: Canon-typical vulgarity, Suicide, Suicide Attempt, Death Experimentation, Temporary Character Death, Blood & Gore, Minor Character Deaths

Disclaimer: i do not own bnha, obviously.

Heads Up: I changed the title to the Series Title and I'm just gonna shove these all in chronological(ish) order. So they're [Title: Summary] for the first chapter and [Title Chapter Number: Chapter Title] for the subsequent ones. All intermissions/addendums will be labeled. There wil be time skips. Enjoy.

Terminal Velocity: Summary
Katsuki drives Izuku over the edge and, together, they discover Izuku wasn't quirkless after all. Rekindling their childhood friendship, Katsuki and Izuku begin to test out the limits of Izuku's incredible new quirk. It is a very messy process.

Terminal Velocity 1: friends again
Katsuki discovers firsthand that Izuku has a quirk after all.

Katsuki panted as he jogged back up the concrete path to the school building. Of fucking course, he'd forget his stupid fucking history assignment in the classroom today of all days. It was hot outside and miserable under his black uniform. He'd been most of the way home, too, which only made everything fucking worse.

Hopefully the school building was still unlocked and he could slip in without any trouble. Most of the clubs were probably finished by now. Katsuki couldn't hear or see any of the sport clubs out in this heat, which made sense. He wouldn't have been out in this weather if he'd had a choice about it.

Slowing down, he was about ten feet from the front door when he saw a shadow pass over the ground. Katsuki looked up. He saw something black against the blue sky. His eyes focused on it, recognized the black as a school uniform, identified the curly dark hair and the pale face beneath it.

As his brain put a name to that face - Deku- he realized that the idiot was falling head first.

And he was aimed right for pavement.

The sickening sound of meat slapping concrete, the slick splatter of blood, the sharp crack bone, filled the air. All other sounds went utterly silent except for Katsuki's ragged breathing. Deku hit the ground once and with enough force that he bounced once and landed again, his broken body sprawled across the pathway in front of Katsuki.

Katsuki forgot his homework entirely. All he could think was that he had run back to the school to see this. To see Deku jump. To see the slow spread of bright red blood on the ground. To see the mangled body and bones. To see a split skull with red stained tissue leaking out of it. To see sightless eyes staring out at nothing, not at Katsuki, not at the sky, just off to the side.

What had been Deku's last sight? What had been his last thought? Why had he jumped?

Katsuki took a half step back. He didn't need to ask that last question. He knew why. It was clear as day. It rang like a bell in his head. How many times had he told Deku he'd be better off jumping to his death? How many times had he told him it was better to be dead than quirkless?

"Fuck," Katsuki whispered. He didn't know what else to say or who to say it to.

All at once the buzzing sound of insects started up again. Except it wasn't quite right. Except it was too loud. Except it came from in front of Katsuki. Except it started to sound like the snapping of wood or bone.

Except Deku's body was moving.

Katsuki took another step back. "What the fuck."

Deku rolled over and gasped. There was blood on his skin, but as Katsuki watched, his limbs pulled back into the right position, the right shape. The tears in his clothing remained, but through those holes, Katsuki could see Deku's skin repairing itself. There was something around him, moving and shifting, like grains of black sand. As the scratching, insect-like sound ended, so did the shifting sand.

Soon, the only noise was the rasp of Deku's labored breathing. Katsuki stared, transfixed, with his tongue stuck to the roof of his mouth, his eyes wide and his heart in his throat, hammering harder and harder.

Deku closed his eyes. Deku opened them again. He sat up slowly, looking around him. There was blood all over the concrete. Blood all over him. Blood even on Katsuki. He had felt it impact on his cheek and there had to be more hidden in the black of his uniform.

"Deku?" Katsuki asked his throat tight. The word came out as a croak.

Deku blinked once and turned to look at him, "Kacchan? What… what happened?"

"You died," Katsuki said. "You hit the ground and died and then you-" he gestured towards him, towards the ground and his body, "You twisted around and fucking came back to life. What the hell did you do, Deku!?"

Deku stared down at his hands, at his clothes and then looked up in confusion again at Katsuki. "It didn't work?" Tears welled up in his eyes, which was really unsurprising to Katsuki. Deku cried over everything, as far as he was concerned. "I can't even kill myself right?"

Katsuki found it hard to breathe around the ice in his chest. He had been right in his assumption. Deku had been trying to kill himself. Fuck. Fuck. What did that even mean?

It came to him so suddenly, Katsuki's back jerked like he'd been struck with a short shock. "A quirk. That's your quirk. You fucking have a quirk!"

Deku wiped at his face with his arm, smearing blood across his skin. Tears were flooding down from his eyes and he kept scrubbing at them. "W-what?"

"Think about it!" Katsuki said, taking a step forward. He stopped there because of the blood on the ground. "Can doctors really test for a death quirk? No. Of course not! So this has gotta be your quirk!"

"I have a-" Deku's eyes widened. "But I have the joint in my toe! They said I don't have a quirk!"

"You fucking broke your skull open on the fucking ground in front of me," Katsuki shouted, his voice harsher than usual. He was never going to forget that image. He wasn't about to let Deku forget either. "You fucking died." He gestured to the blood, "There's no fucking way you should be sitting up and fucking talking, idiot Deku. Can you stand? Can you walk? Are you hurting anywhere?"

Deku looked at his hands, opening and shutting them a few times before he got up to his knees and then to his feet. He swayed for a second and then found his balance. Standing up in the center of the blood splatter, he seemed to see how much there was for the first time. He went pale and quickly looked up from the ground, "I have a death quirk?"

"Well either that or you're cursed to not be able to kill yourself or some shit, I don't fucking know," Katsuki said. "All I know is that you didn't die from this fall."

"Maybe it wasn't high enough," Deku said thoughtfully. "Should I try again on a taller building?" Then he paused, wincing, "Falling like that hurt a lot, though… Or at least, the putting myself back together did."

Katsuki's stomach churned at the thought of Deku hitting the ground again. Behind his eyelids, there was that bounce, that blank gaze, and all that blood, flashing in front of him each time he blinked. He opened his mouth but didn't say anything, couldn't. He closed his mouth again and rubbed it with his hand. Deku looked up at him, interrupting his own mumbling.

"What if I can only die and come back once?" Deku asked, "What if it doesn't work a second time?"

"Then you wasted your shitty quirk already," Katsuki said. He could answer this. It was obvious. "And you might as well be quirkless still. It's not like anyone is going to fucking believe you if you can't do it again."

Deku's hands tightened into fists. "Do you still think I should die if I'm quirkless?" he asked, "If I have a quirk, will you be my friend again?"

Katsuki blinked. At twelve years old, having a quirk was all that seemed to matter. It had been the most important thing in his life for years. Deku had been worthless because he had had no quirk and had still tried to be better than Katsuki. He had pitied Katsuki. Katsuki knew he had, he had seen that sad look on Deku's stupid face so many times.

But if Deku had a quirk that made it impossible for him to die… Well, he probably wouldn't be as good a hero as Katsuki, that's for sure, but he could be a rescue person. Or he'd probably be a good teammate, considering how explosive Katsuki's own quirk was. He wouldn't have to be afraid of hurting Deku. Deku could heal from death. He could heal from anything.

Katsuki nodded. "If you have a quirk, I'll be your friend again."

Deku clutched the front of his ruined jacket with one tight fist. "Really? You promise?"

"Yeah."

Deku closed his eyes, taking in a deep breath. Letting it out slowly, he looked up with determination shining in his green eyes. "Okay. Let's find a taller building."

Katsuki looked at the blood on Deku's face and nodded.

The bounce was worse this time. The blood splatter larger. Katsuki had to clap both hands over his mouth to keep from vomiting at the sight, the smell of spilled organs all over the ground. But it worked.

It worked.

Deku's body pulled back together on its own. He sat up, slowly, breathing evenly and shaking only a little bit. When he sat there for longer than a minute, just breathing, unmoving, Katsuki stepped forward.

If his hand was shaking when he reached out to Deku, neither one of them said anything. After all, Deku was trembling as well.

"I have a quirk," was the first thing he said to Katsuki as he was pulled to his feet. His eyes were shining. There was an excited flush to his face. "I have a quirk!"

Katsuki tightened his grip around Deku's hand. "Yeah. You do. Now c'mon. People saw you fall, we gotta get out of here." He tugged on him, pulling him away.

As they left the scene, left the blood all over the ground, and walked away with their rekindled friendship, Katsuki heard Deku whisper, "Will I come back from any death?"

[part 1 of 3]