Actions

Work Header

Inoculate

Summary:

Midoriya Izuku has a powerful nullification quirk. He can inoculate himself to any emitter-type quirk. The problem? It’s blood based.

Meaning his father isn’t Midoriya Hisashi. His father is a vigilante his mother met in her wilder days:

Chizome Akaguro (The Hero Killer: Stain).

Chapter 1: Prologue: First Blood

Chapter Text


“Mom! Mom! Mom!” Izuku said, jumping around on his tiny feet. “I got my quirk! I got my quirk!”

 

“Is that right, Izuku?” his mom asked, sounding confused. The doctor had told them he was quirkless. They had the foot x-ray to prove it.

 

Izuku nodded and opened his mouth wide to show her his tiny fangs. “Kacchan fell in the river and cut his hand and I went to help him and he was bleeding so I licked his hand and my quirk showed up and he tried to blast me in the face but it didn’t work at all. It didn’t even hurt and he got really mad, but I think it means that I’m able to stop other people’s quirks if I drink their blood! Isn’t that cool, Mom? I know it doesn’t match you and Dad’s quirk, but it’s still super cool and useful for hero work. I wonder if I could become a hero like Blood King, but I can’t control blood like he can. I wonder if there are other heroes like me. What do you think, Mom?”

 

His mother had gone very pale, and she was staring at him with horror and worry. When Izuku looked up at her with big, hopeful eyes, she coughed and awkwardly said, “I don’t know, honey, we should look some up. You go start up the computer. I have to call someone real quick, okay?”

 

Izuku, ever the observant child, gave her a keen look but dropped the subject to do as she said. The moment he was out of sight she leaned her weight into the counter to stay upright and placed her hand over her chest. Oh, this was bad. This was very bad.

 

She would need to call Hisashi. To let him know of this development. And she would need to call him…

 

It’d been years. She didn’t know if the number she had was up to date, though Hisashi might be more in the loop. Even if he was in a different country, he was still running in their old circles. Either way, she couldn’t keep it from him . He had the right to know, and maybe… just maybe, if he were still in Japan, he could be a real father to Izuku…

 

Oh god, this was a terrible idea.


 

“Mantis,” the man said, eyes shooting around the room, marking the escape routes. They were in a quiet bar at the edge of town. The lighting was dim and tired. Classic rock played on the jukebox in the corner. The place was clean and lowkey, but the patrons were seedy, keeping their eyes down, the few who talked kept their voices low.

 

Then he looked over the woman. She had weapons, of course, but she wasn't overly armed. She’d also gained weight, looking softer and sweeter than she had before. It was no wonder, really, because beside her was obviously her first child. He had green curls and was face-down on the table sleeping. It was probably way past his bedtime, which made him wonder why she brought him in the first place. He was especially vulnerable, all things considered.

 

“Stendhal,” the woman said. There was a nervous energy around her. He supposed some things never changed. “It’s been a while.”

 

Stendhal slid smoothly into the seat across from her. “Let’s not waste time on pleasantries, Mantis. There’s a reason you called me here. What is it?”

 

Mantis’s mouth thinned into a line, and her eyes took on a harder glint. “Do you remember five years ago when we went undercover to take down Hela’s Wolves?”

 

Stendhal’s eyes narrowed dangerously behind his mask. “Don’t tell me they’re back.” He hissed.

 

Mantis shook her head, her dark hair falling in waves around her shoulder. Her domino mask was simple, and it didn’t hide how beautiful she was. “No.” She clarified. “Do you remember what we did while undercover?”

 

Stendhal frowned. They had done a lot of things when undercover. She needed to be more specific. His eyes shot to the five-year-old beside her, and it clicked.

 

“You can’t be serious.” He said. It was rare that he was actually shocked, but this was one of those moments. “We used protection!”

 

“Apparently it wasn’t enough,” Mantis said cooly.

 

“But Salamander--” Stendhal shook his head. She was supposed to be with Salamander. They’d been together for as long as Stendhal had known them. They were a dangerous team at the best of times, with morals and convictions to match their skill.

 

“We thought he was his,” Mantis said, looking slightly guilty, “but my son’s quirk manifested recently. And it’s blood-based. We can get a DNA test if we must, but you and I both know why that isn’t a wise idea.”

 

Stendhal just stared at her, taking in this new reality. “I have a son?”

 

Mantis nodded.

 

Stendhal continued to stare at her, his expression hidden by his mask. “This boy is my son?”

 

Again Mantis nodded and Stenhal put his hand over his chest. He had a son. He had a progeny. Somehow through fate or providence he had a child now, with the vigilante Mantis of all people. This wasn’t part of the plan. This was so far from the plan that Stendhal didn’t know what to do with this information.

 

He would take responsibility, of course. Who was he to go against destiny? But still, he wasn’t prepared for this. He didn’t know what it meant to be a father. He could not give up on his work, his mission to make the world a better place. But he couldn’t abandon this child, either. Perhaps he could be shaped... molded into a successor. Perhaps that was fate’s will! But it was a dangerous decision.

 

“Sweetie, wake up,” Mantis said, shaking the child. The green-haired boy woke slowly and yawned tiredly. He, too, wore a domino mask, looking entirely too young for there to be much point in concealing his identity. It didn’t matter, however. This was a dangerous place, and Mantis would take whatever precautions necessary to protect the child. Five years were a long time to be retired in the underground, but people still remembered the kind of bloodshed Mantis could cause, and they weren’t eager to cross her.

 

Stendhal took note of the small fangs in the boy’s mouth. Those weren’t his, but he supposed a mutation of his quirk. Fascinating.

 

“Sweetie,” Mantis said, entirely too doting. “Remember the man I told you about?” The boy frowned, looking over the man and pulling into himself shyly. “This is him. This is Stendhal.”

 

The boy had green eyes like Mantis, and they were equally calculating, which was surprising on someone so young. “Hello,” he said softly.

 

Stendhal stared at the boy, almost hungrily, taking note of everything. He was obviously untrained, but that was to be expected of one so young. He took after his mother, everything from coloring to face shape. But he had freckles. Stendhal had grown out of those, having let them go pale from working so many night shifts, but he used to have them, so that was something in common. They had similar eyebrows, he supposed, and he probably got his curly hair from Stendhal’s mother. They had similar hands, the child’s looking disproportionately big in a way that implied an awkward growing period in the future. Stendhal remembered how awkward he’d been in his teenage years. He would not envy the child when he got there.

 

Really, there wasn’t much of him in the boy as far as appearances went. But Stendhal couldn’t see what angle Mantis could possibly have lying to him. He nodded to the boy.

 

“Stenhal, give me your hand.” Mantis ordered. He should have known she’d become a mother eventually. She had the mom voice down. Stenhal’s eyes narrowed at the woman, but he gave her his hand cautiously. He knew she was the kind of woman you were better off not trying to fight on minor things. She had ways of getting her way.

 

Mantis pricked his finger with one of her needles.

 

Faster than even Stendhal could follow, he found his finger suddenly in the child’s mouth.

 

Stendhal flinched back and glared at the boy.

 

He flushed and looked properly guilty. “S-sorry,” he said softly. “Instinct...”

 

Stendhal narrowed his eyes slightly, then arched an eyebrow at Mantis. Izuku would apparently match Stendhal’s speed one day.

 

“Our son’s quirk nullifies the quirk of those whose blood he drinks,” Mantis said cooly. She put an arm around her son’s shoulder. “If you ever try to use your quirk against him, it won’t work.”

 

Stendhal stiffened. “You tricked me.”

 

Mantis smiled thinly. “You don’t have a reason to use your quirk on my son, anyway, right?”

 

Stendhal snorted. The boy looked very confused. The vigilante reached out and shuffled the kid’s hair, and he flushed bashfully.

 

“What’s your name, kid?”

 

The boy shot his mother a look for permission. She squeezed his shoulder, and the boy turned back to him.

 

“It’s Izuku.”