Heaven's Warrior (Seraph of the End x Reader x OC)

Prologue

* ~~, ~~, somewhere in America, in a research lab *
"You never said it was female."

The doctor in the lab coat squinted, not quite able to see the man in the black suit before him due to the darkness of the room. He glanced at the child strapped to a metal research table and shrugged.

The markings in her skin were completely gone now, but he had seen the scripture in her skin with his own eyes. He knew this child was what the man in the black suit wanted. "She had the markings you described on her skin, but they were made of light," he explained, only now realizing how crazy he sounded, "not of something that resembled dark ink. I didn't know it mattered what gender it was as long as it was who you were looking for."

The man in the black suit frowned, his features barely recognizable past the shadows darkening his face. His eyes glowed when he turned to lock gazes with the scientist. "She isn't what I was looking for. I must even say I myself am not sure what she is exactly."

"W-well," the doctor blurted, adjusting his glasses on his nose, "her physiology is that of a human, but her body reacts unlike a human would to certain stimuli."

"Explain further."

The doctor cleared his throat stiffly. He knew nothing of the man except that he had payed a world of money to have the girl analyzed in the lab, and then another few millions to see her when results were sent to him of the various experiments conducted on her. To come all the way from Japan—to have known there was a parentless child with strange abilities in the other side of the world—there was something the doctor didn't know. But he wasn't about to discuss. "She heals inhumanly quickly, for starters. We have inflicted severe wounds to her body—several that would kill her if left unattended enough time—and her whole body stops normal functions to heal the wound. Small cuts heal instantly, cuts to arteries and veins stop bleeding and heal in a matter of seconds, broken bones heal in a matter of minutes... Whenever she goes out of regular human functions, the strange markings appear in her body.

"I agreed to cutting off an arm. It took her no more than a minute for her flesh to rejoin the lost limb back to its place. The interesting thing is that her whole body stopped working—the only working tissues and organs were those of the respiratory system, including the heart and blood vessels, along with the tissue and bone where her arm had been severed. She should have died." The doctor sighed, his mind rushing. "It's almost as if she is a god trapped in a human body—she is human enough to be able to die, but divine enough to make that impossibly hard."

The man in the black suit hummed. He walked toward the child but stayed hidden by shadows. His movements were perfectly silent as he leaned down over the girl and eyed her for the very first time.

Tangles of (h/c) hair were sprawled around her young face. Her skin was smooth but clammy, obviously paler than it would have been in any other circumstance. Her eyes were cracked open, directed upward toward the ceiling but somehow unfocused, unseeing, as if she was dead. She was breathing shallowly, her body exhausted but alive. Despite having been so brutally experimented on, as the doctor had said, she looked unharmed.

She was not the child the man had been searching for, but she certainly peaked his interest. Being a vampire, the man could distinguish perfectly the smell of humans. The doctor was certainly one, but he couldn't tell if the girl was one or not.

She sort of smelled like a human, but she also had no smell. It was like smelling a strong scent but being so accustomed to it, you no longer perceived it.