Chapter Text
ACT I — THE BOY WHO CAME BACK
PROLOGUE
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It all started on a normal evening.
For Izuku Midoriya and Katsuki Bakugo, life had never been normal. And in the world they were born into, "normal" was nothing but a memory.
The apocalypse came without warning. The dead rose, broken and snarling, half-skulls grinning through sheets of rotted flesh. Their groans carried through the night like a warning bell, and every snapped twig or rustle in the dark sent hearts racing. Survival wasn't living—it was clawing through each day, praying the next wouldn't be your last.
Most survivors built camps, clinging to each other like driftwood in a storm. Izuku and Katsuki had done the same. Their camp was nothing more than a collection of scrap walls and patched roofs, but it was home. Behind those barricades, there was laughter, shared meals, even fleeting moments of peace.
For Izuku and Katsuki, peace meant standing side by side. They were fire and stone, blade and shield. Katsuki was reckless fury, Izuku was calculated caution, and together they made survival possible. Friends wasn't the right word—blood and sweat had fused them into something stronger.
But even that bond couldn't stop what came next.
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The supply run was supposed to be like any other. Dangerous, exhausting, but something they had done a hundred times before. Izuku and Katsuki knew how to move through the ruins of the old world, how to listen for the slightest sound, how to fight when the dead came crawling out of the shadows.
But that day was different.
The streets that once felt familiar became a battlefield. They fought their way through waves of infected, every swing, every bullet, every desperate breath pushing them closer to the edge. By the time they made it back to camp, they were alive—but barely. Their clothes were torn, their bodies bruised, and their skin was covered in dirt and the remains of everything they had fought through.
For a moment, they thought they had made it.
Then Izuku saw it. A jagged mark along his arm, hidden beneath the grime and blood. A wound he hadn't noticed in the chaos. A bite.
The world stopped.
Every sound around him faded—the voices of the camp, the crackling fire, even Katsuki calling his name. All Izuku could see was the mark staring back at him, a death sentence carved into his skin. Because he knew what came next. He had seen it happen to others. The fever. The change. The moment someone stopped being themselves and became one of the monsters they spent every day fighting. And the worst part wasn't dying. It was knowing Katsuki would be the one forced to watch.
"We can hide it," Katsuki had said, his voice sharp with panic as soon as he realized what Izuku had found. "No one has to know. I'm not killing you, damn it!"
For once, Katsuki wasn't angry. He wasn't yelling because he was frustrated. He was terrified. Izuku looked at him, and that fear hurt worse than the bite itself. "I'm infected," Izuku whispered, his voice breaking. "Kacchan... I'm infected."
Katsuki stepped closer, refusing to accept it. "You don't know that."
"Yes, I do." Izuku's hands shook as he looked away. "I'll turn. I'll become one of them."
"You're not them."
"But I will be." The silence between them felt heavier than the entire ruined world outside their walls. Katsuki tried to argue, tried to convince him there was another way, but Izuku had already made his decision. Because Katsuki was the one person he couldn't lose. And if staying meant becoming a monster and making Katsuki put him down, then leaving was the only choice he had left.
So before Katsuki could stop him, before anyone could see the tears he refused to let fall, Izuku packed what little he could carry and walked away.
Away from the camp.
Away from safety.
Away from the only person who had ever made the end of the world feel survivable.
That was the day Izuku left. The start of it all.