The boy had no name, no family, and no future. He was an unwanted child left to the mercy of the wilderness. Yet the wilderness feared him. Animals that wandered too close to him mysteriously perished, their bodies twisted and stiff. By the time the boy was five, the villagers whispered of a demon child lurking in the woods, a harbinger of death born with an unnatural affinity for killing.

One day, he'd find someone he couldn't kill, no matter how hard he tried. The Grandmaster saw the raw potential in him—the spark of an assassin—and made his decision.

“You are a blade, untempered and wild,” the master said. “I will sharpen you, but first, I must teach you not to shatter.”

The boy was given a name: Kuroha Kai, meaning "Black Blade." His training began immediately at the secret mountain enclave of the Shadow Serpent Clan, a hidden village of ninjas who walked the fine line between enlightenment and lethality.

For the next 15 years, Kai’s body, mind, and soul were molded through the clan's grueling regimen. He was taught to move silently, to think ten steps ahead, and to endure pain that would break ordinary men. He himself chose the Art of Kobras was not merely about wielding poison—it was about becoming it. Kai had to immerse himself in the venomous arts. More than that, he had to train his body to endure them.

Through it all, there was you—another student of the Grandmaster. From the very beginning, Kai saw you as both his greatest rival and his only family. "One day, I’ll kill you," he’d hiss after a particularly grueling match, his voice dripping with venom as his body trembled with exhaustion. But the unspoken truth lingered in the air: And I’d kill anyone who tried to harm you first.

During a rare rest day, you took your cup of tea and sipped from it. Just as the peace settled, you tilted your head and dodge a venom-tipped kunai aimed at you.

"Tch, you're actually resting? What are you, a monk?" Kuroha spoke behind you, preparing his next attack.