Rei's first week was a disaster of carefully maintained control.
She sat next to Midoriya in every class, close enough to smell the faint scent of mint and old books that clung to him. Close enough to feel his heartbeat spike whenever Present Mic called on him. Close enough to notice that his hands shook slightly when he wrote, scarred fingers gripping pens too tight.
She learned his patterns. The way he muttered when thinking. The way his eyes tracked everyone's Quirks, cataloging, analyzing. The way he flinched when Bakugo's voice rose above a certain volume—not from fear, she realized, but from memory .
On Friday, it happened.
They were in Basic Hero Training. Cementoss had constructed a disaster simulation: a collapsing building with civilian dummies inside. Teams of two. Rei watched the assignments scroll across the screen, her stomach tight.
Team 12: Kazuki Rei & Midoriya Izuku
"Yes!" Midoriya's whisper was fervent. He turned to her, practically vibrating. "Kazuki-san, your Quirk is perfect for structural stabilization! If you nullify the kinetic energy of falling debris, I can focus on evacuation and—"
"Rei," she interrupted.
"What?"
"Call me Rei." She stood, offering her hand. "Partners?"
He took it. His palm was warm, scarred, and calloused in ways that spoke of bones broken and reset, of pain endured and overcome. Rei felt his pulse through the contact—fast, excited, alive.
"Partners," he agreed.
The simulation began.
It went wrong immediately. The building's collapse pattern was randomized—Aizawa's doing, the bastard—and a support beam shattered in a way that defied structural logic. Rei saw it falling toward a cluster of civilian dummies, saw Midoriya diving toward them, saw that he wouldn't make it in time.
She didn't think.
Rei's Quirk exploded outward. Fifty meters of perfect nullification. The beam froze mid-air. Dust particles stopped drifting. Even the sound seemed to deaden in her field.
But she'd forgotten the cardinal rule: energy cannot be destroyed, only transferred.
All that kinetic energy—all the force of the falling beam, the collapsing structure, the very motion of the air—had to go somewhere. It flooded into her like a tsunami into a teacup.
Rei screamed.
She felt her feet leave the ground. Felt her hair whip upward, gravity itself nullifying around her. The energy wanted out , and she was the only vector available.
"REI!" Midoriya's voice, distant and underwater.
She saw him running toward her, saw the idiot running toward the girl who was literally radiating destructive force, and she tried to warn him, tried to push him away with her Quirk, but—
He grabbed her hands.
The overflow discharged.
When Rei woke, she was in Recovery Girl's office. Her head felt stuffed with cotton. Her Quirk felt... quiet. Empty.
"You discharged approximately four hundred thousand joules of kinetic energy through young Midoriya," Recovery Girl said, not looking up from her clipboard. "He's fine, by the way. Somehow. That boy's durability defies medical science."
Rei sat up too fast. "Where—"
"Next bed."
She turned. Midoriya was indeed in the next bed, bandaged but conscious, reading his notebook. When he saw her looking, he smiled—that same terrifying, earnest smile.
"You're awake! I was worried—the discharge was incredible, Rei. The way you channeled all that force through a single vector point instead of exploding outward? That's advanced technique. Did Shiketsu teach you that?"
"You..." Rei's voice cracked. "You grabbed me. I could have killed you."
"Nah." Midoriya closed his notebook. "I knew you wouldn't."
"How? You don't know me. We just met."
He tilted his head, genuinely puzzled. "Because when you look at people, you see where they're going to move. You track vectors, right? Trajectories?" He pointed at himself. "My trajectory was toward you. You saw it. You could have pushed me away with your Quirk—nullified my kinetic energy, made me stop. But you didn't."
Rei stared at him.
"You trusted me," he said. "So I trusted you back."
The door burst open. Aizawa stood there, looking like he'd swallowed a lemon. "Both of you. Principal's office. Now."