Age: 11
Nitroglycerin
It is a fascinating and terrifying molecule. In my previous life, it was an oily, unstable liquid used to make dynamite or treat angina. Here, it is my sweat.
I was sitting on the high branch of an old oak tree in the municipal forest, staring at my right palm. The midday sun filtered through the leaves, creating patterns of light on my skin.
To the rest of the world, my Quirk is simply "go boom." You move your hands, bright lights come out, the enemy falls. Comic book magic. But the biological reality is much more brutal.
Physics is relentless. Newton's Third Law makes no exceptions for protagonists: "For every action, there is an equal and opposite reaction."
If I fire an explosion strong enough to knock down a concrete wall, my shoulders have to absorb a force equivalent to the recoil of an anti-tank gun. In my previous life, the first shot would have dislocated both my shoulders. The second would have ripped my arms off.
But here...
I clenched my fist, feeling the skin of my palms. It was thick, hard, almost like fire-cured leather.
There is a scientific theory in this world, often ignored by the general public, about "Somatic Quirk Adaptation." Basically, it says that human evolution accelerated to stop us from killing ourselves with our own powers. My bones are denser than reinforced steel. My ligaments have the elasticity of industrial cables. My eardrum has an extra membrane so I don't go deaf from my own detonations.
I am a human tank in a pre-teen's body. But even tanks have limits.
"Kacchan, your heart rate is dropping. Are you ready?" Izuku's voice came from below.
I looked down. Izuku, at 11 years old, no longer had that baby fat on his face. He was thin, but it was a wiry thinness, the result of three years of following my hellish calisthenics routines and running through the forest. He held a stopwatch and his inseparable notebook.
"I'm calculating the viscosity, nerd," I replied, jumping down from the branch.
I landed softly, bending my knees to cushion the impact. Thanks to that enhanced bone density, a three-meter drop felt like stepping down a stair.
"Today's heat is optimal," I muttered, opening and closing my hands. I felt the moist, dangerous layer accumulating. "Ignition should be instant."
"The goal is aerial mobility, right?" asked Izuku, moving to a safe distance behind a thick tree. He put on some safety goggles we had bought at a hardware store.
"Not just mobility. Vector control."
I raised my arms behind me, palms open. It wasn't about releasing full power. If I did that, I'd go flying uncontrollably like a deflated balloon. The trick was to create continuous micro-explosions. A human jet engine.
I took a deep breath, tensing my abdominal core. If my abs weren't rock hard, the force would fold my spine in half.
BOOM!
The sound was dry, concussive. I didn't launch myself at an enemy. I launched myself at the sky.
The ground disappeared beneath my feet. The wind hit my face. For a second, I was a rocket. The sensation of weightlessness mixed with the raw violence of the explosions was intoxicating.
But then, physics claimed its price.
My right hand detonated a fraction of a second later than the left due to an imperfection in sweating. The imbalance was catastrophic.
I went into an uncontrollable tailspin four meters up.
"Shit!"
I spun in the air, watching the world go round. Tree, sky, ground, tree. I had to release a corrective explosion with my left hand to stop the rotation, but that killed my upward momentum.
Gravity grabbed me by the ankles and yanked me down.
I fell.
But I didn't fall like a sack of potatoes. Years of judo and parkour took over. I rolled over my right shoulder as I hit the grass, dissipating the kinetic energy, and ended up crouched, skidding a few meters, smoke rising from my hands.
My arms throbbed. A dull ache, deep in the bone. Micro-fractures, probably. But they would heal by tomorrow, stronger than before. That was the blessing and the curse of this body.
"Max height: 4.5 meters!" Izuku shouted, coming out of his hiding place. "And you stayed in the air 3.2 seconds before losing the axis!"
I stood up, brushing the dirt off my shorts.
"The delay in the right ignition was 0.05 seconds," I grumbled, frustrated, ignoring the pain. "Enough to destabilize the flight. My glands have to fire in perfect unison or I'm a dizzy duck."
Izuku was already writing furiously, muttering to himself.
"Maybe if you change the angle of your wrists..." he said, without looking up. "If you open your fingers instead of cupping your palm, you could disperse the force to gain stability, even if you lose lift power. Like... like the ailerons of a plane."
I stopped. I visualized the fluid mechanics in my head. By opening the fingers, the explosion wouldn't be a concentrated jet, but a fan. Less vertical thrust, more horizontal control.
"Dispersal for stability..." I repeated. I looked at Izuku. That brain of his was going to be more dangerous than my nitroglycerin one day. "Not a bad idea."
I cracked my neck. The pain in my arms was already subsiding. My accelerated metabolism was working.
"Let's try again. And you, stop hiding behind the tree. If I miscalculate and explode backward, I need you to analyze my posture in the air, not take cover."
Izuku smiled, that nervous but brave smile he had cultivated under my tutelage. He adjusted his safety goggles.
"Yes, Kacchan!"