Izuku arrived home clutching the burned remains of his notebook, hoping he could slip up to his bedroom before his mom noticed. He could hear her cooking in the kitchen. He crept up the stairs.
"Why are you home late?" Tenko demanded, standing at the top of the stairs with his arms crossed.
Izuku winced. He'd avoided his mom, but instead run straight into his cousin. Tenko Shimura had been living with the Midoriyas ever since the rest of his family had died in a tragic car crash. Inko had been adopted as a baby and unaware of her biological relationship to Kotaro Shimura before his death, but she'd still taken his son in. Izuku loved Tenko. The problem was, Tenko was rabidly overprotective.
Tenko's gaze swept Izuku, taking in the dirt stains. He grunted. "I'm going to kill them."
"Wait!" Izuku clung to Tenko's leg. "Please, you'll only cause more trouble."
"Brats like that dare look down on you for being quirkless?" Tenko sneered. "Then I'll show them what a real powerful ability looks like." He tugged on his archer's gloves, the only thing holding back his decay.
"Please!" Izuku begged, jumping on Tenko's back. "I'll play as much League of Legends with you as you want this weekend."
"Why are you so determined to protect your bullies?" Tenko snapped.
"I'm not! I'm trying to stop you from ending up in a juvenile detention center!"
Drawn by the noise, Inko called from the bottom of the stairs, "What are you boys doing?"
They both froze. Guiltily, Tenko said, "We're just horsing around."
Inko said, "Well, go wash your hands, supper is almost ready."
The boys disentangled themselves. Izuku whispered, "What if we send a box of spiders to my bullies? No one will know it was us."
"Deal," Tenko whispered back.
Tenko Shimura had never realized it would be so difficult to collect an entire box of spiders. Video games made collecting animals look easy. But spiders were fast and small. The butterfly net kept missing them. Tenko crouched down on the ground. "Here, little spiders. Huh, maybe an ant would do."
The sky above crackled. Tenko looked up. Two streaks of light came down, one red and one green.
"What kind of freaky meteor is that?" In Tenko's distraction, the box slipped from his hands. The two spiders he'd already collected hopped.
"No! I need a save point!" Tenko leapt after the spiders.
He did not realize the red light was coming at him until it blinded his vision. Then he tried to dodge, but the red followed him.
The touch of the light felt cold as ice. Tenko screamed. It almost resembled water, but it seeped straight under his skin. His spine arched. The coldness had gone deeper. It felt like his blood was freezing. His fingers scrabbled against the dirt. His lungs had stopped working. Then he felt the ice close a fist around his heart.
Tenko remembered the day a teacher had come to take him aside and tell him that his entire family had died in a car accident. His violent quirk awakening had destroyed the office. He counted himself lucky no one had died.
It sucked to be left alone. Now Tenko would be leaving Inko and Izuku to face the same pain when he died.
"Sor…sorry," he whispered. Then the ice hit his brain, taking away all pain and regrets.
The next day at school had been uneventful. Izuku had a vague notion that maybe, just maybe, the bullies had realized they'd gone too far last time.
As he walked home, it started to rain. Izuku put his backpack over his head and ran faster.
As Izuku passed a store window, the dozen TVs for sale all showed the same news channel. The announcer looked genuinely shaken. "A new villain has appeared near Musutafu City Park. We're not sure what power he has, but he seems to be eating quirks. Civilians are advised to evacuate immediately."
Izuku stopped and gaped at the scraggly white-haired youth in the corner of the screen. "Tenko?"
Despite all official advice and common sense, Izuku had not been able to keep away.
He liked to watch and analyze heroes from the roofs of tall buildings. He'd already scoped out every place in the city with a publicly accessible roof. He'd taken the elevator up to the top of the office building. No one had noticed him, because they'd all been running down the emergency stairs.
From the roof, Izuku stared down at the park below.
The trees had been blasted to pieces by spikes crackling with black-and-red light. Tenko stood in the very center. His hair had lengthened and whipped around his head like a halo. His nails had twisted into black claws. Arrow-like tentacles sprouted from each bone in his spine, straight through his shirt. The claws on his toes had ripped his shoes to shreds. His skin looked desiccated. His eyes glowed red.
Even so, Izuku recognized his cousin's face under the red glow.
The bodies of heroes lay fallen all around. The survivors looked afraid. Mount Lady swung a massive leg down.
Tenko easily caught her foot. With a slurping sound, something sucked into his hand. Mount Lady toppled to the ground, a regular-sized human again.
How could this possibly happen? Tenko had decay! He'd never been able to steal quirks!
Without even looking, Tenko shot out a tentacle into Kamui Woods sneaking up behind him. The hero collapsed, the wood vanishing from his body.
The remaining heroes lost their nerve and ran. It did them no good. The tentacles lashed out, consuming each of their powers. Tenko cackled like a madman. The battle was over hideously fast. Tenko stood in the park, as if waiting for more meals to show up.
Izuku stumbled backward, a hand over his mouth as the bile rose up. "Tenko, what happened to you?" he whispered.
He's been possessed by my brother.
Izuku looked around. No one else seemed to be on the roof. "Excuse me? Who are you?"
Look down and to your right.
Izuku saw a green blob lying curled up next to the roof railing. A talking blob wasn't the strangest thing to happen today. "Do you have an ability to turn yourself into slime?"
I'm not a quirk. I'm an alien.
Izuku stared, not sure if he believed this. It reminded him of when the kids at school liked to tell lies to test his gullibility. On the other hand, this thing seemed to be talking telepathically into his head. It couldn't be a normal blob.
My name is One for All. I come from a distant planet. My brother All for One traveled here to feed on primitive lifeforms. He seeded this planet with powers, waited for them to cultivate and become stronger, then returned to eat his livestock.
"Primitive lifeforms? Livestock?" Izuku glared, offended.
Sorry. Those are my brother's words, not mine. He's always been selfish and full of appetite. He doesn't care if he harms the people of Earth when he consumes what he grew inside of you. I came here to stop him. One for All's voice became smaller. Unfortunately, neither of us can interact with this planet without a host. My brother simply possesses anyone who he deems useful. But I refuse to use people without their consent.
Izuku raised his hand, then dropped it because he wasn't sure if a green slime could see. "If I 'host' you, then can you save Tenko? Tenko is my cousin. He seems to be possessed by All for One."
Oh, no. I'm very sorry. Yes, my goal is to forcibly eject my brother from his host, then drag him back home.
"Will Tenko be safe?"
All for One has probably eaten his power by now and weakened his body with overuse. It's only a matter of time before my brother breaks his current host and moves onto the next one. But if we can reach him fast enough, we can save your cousin's life.
"Then what are you waiting for?" Izuku squared his shoulders. "You can possess me."
First, I must make certain you understand what you are asking. Like my brother, I require fuel to possess a host. All for One feeds off quirks. I feed off lifeforce. Every time you use my power, you will shorten your natural lifespan. This is a hefty sacrifice to ask of a small child. I had been hoping to find a hero. Alas, I may be out of time.
Izuku shuddered. "How much life will I lose?"
It's three times as long as how much time you spend using my power. If you use me for five minutes, then you'll lose fifteen minutes off the end of your life.
"That's much better than I was expecting." Win or lose, surely this fight couldn't take more than a few hours. Then Izuku wouldn't lose more than a day of his life. For the sake of saving his cousin, it was an insignificant sacrifice. Izuku knelt down next to the slime. "How do we do this?"
What's your name?
"Izuku Midoriya."
Thank you for your courage and heroism, Izuku Midoriya. I promise that I will make your sacrifice worthwhile. I will do everything in my power to preserve your cousin's life. Please, touch me.
Izuku placed his hand on top of the slime.
It felt pleasantly warm, like a heated towel. The warmth spread up his arm, soothing away his goosebumps. Izuku gasped as the wave of heat rushed down his body. It tingled, almost but not quite painfully.
When the warmth reached his head, Izuku braced himself.
The touch of a foreign mind against his own felt surprisingly soft and gentle. One for All overflowed with compassion and concern for Izuku and his cousin. Izuku could feel how much One for All respected him for making this sacrifice. It made him puff out his chest a little. One for All was a truly kind person, full of determination to protect this world.
You have a beautiful mind too, One for All said. You're someone who naturally helps other people. I can feel your heroism like a burning furnace. We will suit each other very well.
Green wrapped around Izuku's body. Instead of sprouting from his skin, it covered him like a suit. A hood wrapped over his head. Looking at his reflection in the glass wall around the roof, his head seemed to be sticking out of a maw of very sharp teeth. Green tendrils crackled down his body, something between sparks and tentacles.
Izuku looked closer to a villain than a hero. But he knew his cousin would think that he looked cool. The thought made him smile slightly.
"What do we do next?" Izuku asked.
I'm not like my brother. I won't move your body against your will. My power is yours to wield. But I can show you how.
One for All sent the thought, and Izuku instinctively knew what to do. Without thinking, without fear, Izuku launched himself over the roof.
The trees below came rushing up fast. A wave of green light crackled from Izuku's body. He landed on the ground easily in a crouch. His fist left a crater. He'd never felt so lightweight or strong.
Tenko—or the alien possessing Tenko—looked over. Ah, another hero here to become my next snack—little brother?!
I'm here to stop you, big brother.
You silly little child, you should be resting back home. Your body is too weak. I'll bring back plenty of energy for you to snack on. Tenko's body relaxed, the tentacles lowering.
I don't want you to hurt other people in order to bring me energy. One for All's tone filled with determination. I'll stop you from harming these people even if I have to fight you.
You? Fight me? Tenko laughed, except it wasn't a human sound. It made the leaves on the trees wither and die. You're too sickly to even use your power. You'll make your condition worse if you overstrain yourself.
I'm not fighting alone! I have a partner.
One for All and Izuku's wills melded into one. They charged.
Their fist struck a tentacle. Losing all his good cheer, All for One screamed, I TOLD YOU NOT TO WASTE MORE OF YOUR LIFEFORCE!
One for All used his own lifeforce to fight, too. Izuku hadn't known that. But there was no time to question his partner, because the battle had begun.
All for One shot out his tentacles, trying to cocoon Izuku. Together, the boy and symbiote leapt into the air, above the attack. Perhaps a little too far. Izuku was still getting the hang of his power. He landed on a treetop and shouted, "Tenko, please, can you hear me? Please try to fight him."
Little Tenko isn't home anymore. All for One laughed, easily slicing through the tree trunk.
Izuku backflipped and landed behind his opponent. He grabbed a handful of tentacles and ripped, trying to get them out of his cousin. "Tenko! We promised to play League of Legends together!"
All for One howled, sounding angry rather than pained. Red light spread from his feet, latching onto Izuku and holding him in place. All for One's hand shot out—
Izuku screamed, "Tenko, someone is bullying me!"
"HUH?" Tenko's face twisted. His fist froze. "Where are they? I'll kill them!"
Taking advantage of that brief window where All for One had lost control, Izuku lunged. He grabbed onto his cousin by the shoulders and ripped.
Tenko seemed to pop out of the exoskeleton. It collapsed into a red pile of goo.
Grab my brother! Quick! One for All screamed.
But the light vanished so fast Izuku could not tell if it had gone into the air or the ground.
Izuku clutched his unconscious, half-naked cousin, doing his best not to let the older boy fall to the ground. In the distance, sirens wailed. Izuku felt completely exhausted, but he was smiling. He'd done it. He'd been his cousin's hero.
Shooting sounds came from Tenko's handheld game. He gnawed on his lower lip with concentration. Bandaged fingers danced across the controls.
From the doorway, Izuku laughed. "I see nothing can keep you from your games. Shouldn't you be sleeping?"
Tenko looked up with a smile. "I'm feeling at one hundred percent health, thanks to you."
Izuku dragged over a chair and sat next to the hospital bed. He gestured at the bandages covering Tenko's arms and head, then at the IV attached to his elbow. "Your doctors wouldn't agree."
Tenko shrugged. "Eh. Let's say I'm at ninety-five percent." His tone sobered. "Thank you, Izuku. You saved my life. You're a real hero, and you can tell that to every last idiot in your school." Reaching over, he patted Izuku's shoulder.
"That means a lot, coming from you." Izuku blushed. "Would you believe the teachers at Aldera Middle School have all been super nice to me? They're treating me like the new golden boy who can get an A without ever turning in his homework. The principal gave an interview where he called me the pride of Aldera."
Tenko scowled. "Are you going to let them get away with that, after how they used to treat you?"
"Mom feels the same way. We got a huge reward, and she wants to use it to hire a lawyer to go after Aldera for quirk discrimination. Actually, the way they switched to treating me better after I got a power could be used against them."
"Make sure you save some money for support equipment. You wanted to become the first quirkless hero, right?"
"Well." Izuku squirmed in his seat. "It's not a quirk, but I'm not powerless any longer."
"Izuku. That power uses up your lifespan. You need to let it go." Tenko glared.
"I will." Izuku looked down. "It's just, we haven't found All for One yet."
"Then you should let an adult hero fight All for One. I don't doubt that you're as brave as any adult hero, but you shouldn't have to make such a huge sacrifice. Besides, I know you. If someone needs help, then you'll extend a hand, whether it's related to All for One or not. And there are crimes and disasters all over the world every day. It would be too easy for you to start losing up your life every day, until you die. What would that do to me and Aunt Inko?"
Izuku couldn't look up from the floor. "I'll be careful."
"Don't tell me you'll be careful. Tell me that you'll give up One for All."
"Soon. I promise. Hey, we should play games together before visiting hours end."
Tenko allowed the change of subject. He even pretended to be distracted from his concerns.
But after Izuku had left, All for One whispered, See? It's just like I told you. My little brother and your cousin are too reckless and self-sacrificing. They'll both die in pointless heroics if we don't stop them. I don't have any more designs on your planet. Just let me into your body again one more time. I want to take my brother. Then I'll leave, and your cousin's lifespan will no longer drain away. This is your only chance to save him.
Tenko did not reply to the temptation.
But he also hadn't told anyone about hearing All for One's voice. Not yet. He needed to see if Izuku would actually give up the power he'd longed for, the power that would kill him. Because if Izuku would not save himself, then Tenko would save him by any means necessary.