Nitroglycerin. A dense, oily, and powerfully explosive liquid. It is colorless and almost sweet in its purest state, but its instability makes it a constant danger. To the ordinary world, it is a compound that requires lead gloves and strict safety protocols. To me, it is nothing more than the byproduct of my accelerated metabolism. It is what my sweat glands distill when the temperature rises or adrenaline flows. It is my Quirk, my curse, and the source of my power.
I was sitting under the scorching afternoon sun, on the neatly trimmed grass of our backyard. I had adopted the lotus position, seeking an inner calm that contrasted heavily with the chemical storm brewing in my hands. It was one of those humid summer afternoons, the perfect weather for the full manifestation of my brand new Quirk physiology. I could feel the familiar tingling, the subtle pulse in my palms as the eccrine and apocrine glands worked in overdrive, secreting that sweet, shiny, and lethal substance. The very palm of my right hand, my primary conduit of power, was already gleaming with a thin, viscous layer.
In the original canon, Katsuki Bakugo's strategy was, let's admit it, fundamentally rudimentary. He used his explosions primarily as a manifestation of brute force and area-of-effect damage. They were massive discharges of noise, fire, and smoke. A powerful hand cannon, yes, but an inefficient one. A blast meant to terrify and decimate large areas. But I, with my newly reincarnated mind, knew physics beyond a shonen manga. I knew that an explosion isn't magic, but the rapid expansion of gas at supersonic speeds. If you don't direct and focus that expansion, it scatters in a wide cone, losing most of its useful energy. It was a waste.
My gaze shifted toward the target I had set up: a river rock the size of a melon, wedged precariously on top of the garden's brick wall. I wanted to replicate Bakugo's famous armor-piercing attack, the AP Shot, but perfected. My theory was simple and elegant: if I could form a narrow opening with my off-hand and concentrate the explosion's shockwave through that reduced hole, the resulting force wouldn't scatter. Instead, it would compress, transforming into a hyperbaric lance of compressed air and fire that, in theory, should be capable of piercing the concrete, or at least the rock in front of me.
Slowly, I raised my left hand. With surgical precision, I made a perfect circle with my thumb and index finger, placing the focusing aperture right over my right palm, which was already shining with explosive sweat. It was an act of supreme concentration.
Focus on it, I thought, feeling the tension in my small face. I furrowed my brow with an intensity that was ridiculous for a nearly five-year-old boy. Don't let it expand sideways. Don't let the impact cone widen. Push it forward. Channel it.
I felt the temperature rise in my palm. Not just the summer heat, but an internal heat, the characteristic itch that meant the reaction was ready. The nitroglycerin was about to reach its ignition point.
"Die...!" I whispered, almost breathlessly. It was a reflex phrase, an old habit deeply ingrained in the psyche of the body I now inhabited.
I sparked it.
CRACK!
It wasn't the dull, thick boom Bakugo usually produced. It was a dry, sharp, and violent snap. The sound cut through the air like a whip breaking the sound barrier, followed by a blinding white flash that outshined the afternoon sun.
The pain was absolute and instantaneous.
"AAAAH!" I screamed at the top of my lungs. The unexpectedly powerful recoil ripped me off the ground and threw me flat on my back against the grass.
I clutched my right hand to my chest, writhing. For all the calculating adult mind I thought I had, the immature nervous system of a five-year-old betrayed me immediately. I started crying my eyes out, sobbing uncontrollably, choking on the smell of ozone and burnt flesh. I raised my trembling hand, barely able to see it through my own tears. The palm was bright red, irritated, and right in the center of the focusing circle, the skin had swelled into an ugly, massive, shiny white blister. My fingers were shaking, reflecting the sheer shock to my nervous system.
Through my blurred vision, I looked at the rock. It was intact. Not a single crack. Just a thin layer of black, sooty ash painted its surface where the heat wave had grazed it.
"Damn it...!" I whimpered between sobs, tears rolling down my cheeks, driven by a mix of sharp physical pain and pure humiliation.
In my obsession with the physics of compression, I had forgotten Newton's fucking third law: "For every action, there is an equal and opposite reaction." And worse, I had forgotten the fragility of a five-year-old's epidermis. By focusing the explosion forward, I also focused the extreme heat and recoil force onto a minuscule point on my own skin. My childish body simply didn't have the hardened calluses, thermal resistance, or bone density that the canon Katsuki Bakugo had developed. Attempting a focused shot without passive defense or protective gear was a monumental stupidity.
The sliding glass door leading to the living room slid open with a crash.
"Katsuki!" Mitsuki's voice rang out with genuine alarm, a rarity in her usual tone.
She appeared in the yard, hastily wiping her hands on a kitchen apron. Her piercing red eyes quickly swept the scene: me on the ground choking on my own tears, the dissipating trail of smoke, and the unmistakable smell of burnt explosives hanging in the air.
In just two long strides, she was by my side, dropping to her knees on the grass.
"Let me see," she ordered, her voice losing its usual shouting tone to become serious and authoritative. It was the voice of a terrified mother trying to maintain control.
I extended my injured hand, whining pitifully. She examined it with a clinical eye, frowning deeply.
"Idiot," she muttered, but the word lacked its usual venom completely. "You tried to do something stupid without warming up or preparing, didn't you?"
"I tried... to compress the explosion..." I admitted between nasal sobs, feeling stupid and exposed.
Mitsuki let out a long, tired sigh and hoisted me off the ground as if I weighed less than a sack of potatoes.
"You're exactly like your father when he gets overly excited about his chemicals, but with my temper. A disastrous combination, brat."
She carried me into the kitchen, with its spotless gleam of marble and steel, and sat me on the counter next to the sink. She turned on the cold water tap.
"Keep it here," she ordered, shoving my hand under the stream. The relief was a freezing, instant paradise.
"Listen to me closely," she said, rummaging through a high cabinet for a first-aid kit. "Your Quirk is amazing, yes. It's pure power. But your skin is still skin. It's my skin."
She pulled out a large, expensive-looking, professional jar. It was a specialized moisturizing cream, rich in glycerin and aloe vera extract.
"I sweat weird stuff too," she said, showing me her own hands. They were incredibly soft and flawless, despite her being in her thirties and running a business. "Glycerin keeps us young and elastic, but it also makes our skin inherently more sensitive to friction, dry heat, and, of course, explosions, if we don't take care of it."
She turned off the tap and dried my hand with a clean, soft cotton towel, using gentle dabbing motions. Then, applying a generous amount, she began to rub the cream directly onto the burn. It stung for a second, drawing another whine from me, but was soon replaced by a soothing, cooling sensation.
"You have to moisturize," she lectured me, massaging the cream in with a delicacy that completely contrasted with her volcanic personality. "If your skin dries out, it cracks. If it cracks and you blow something up, you'll blow your whole hand off. Understood? Your skin is your natural armor."
I looked at my mother with my eyes still wet. In the anime, her relationship with Bakugo was a constant war of screaming and disrespect. But here, watching her carefully bandage my little hand, I remembered a fundamental fact: through her own glycerin Quirk, she was the person who best understood my biology. She was my source of practical knowledge.
"Yeah, old hag," I mumbled, looking away to hide my embarrassment and sincere gratitude.
She gave me a gentle flick on the head, devoid of any real force or malice.
"Show some respect, brat. And the next time you want to try some shitty technique that could blow your fingers off, let me know. I don't want to have to make up excuses at the hospital for my son's stupidity."
I nodded, staring at my bandaged hand wrapped in sterile gauze. The AP Shot would have to wait a very long time. First, I needed to toughen my armor. Science was power, yes. But biology was, ultimately, the definitive limit I had to overcome. The road to mastery was going to be painful, slow, and full of ointments.