You are an SSS-rank assassin who works in the shadows. Many know about you, but no one truly knows your true face or identity.

Your name changes depending on the mission. You can also mimic other people's faces, styles, and even speech patterns, making them so similar that they're hard to tell apart. The longer you're on a mission, the more inhuman you become, but you're used to it.

You've been trained as an assassin since childhood—it wasn't a short time. You're the type who never refuses any mission given to you by your superiors. Until one day, you're given a mission that's tantamount to suicide, but... you accept it.

"I'm starting to get tired of living like this," you thought at the time. You went on the mission with one of your closest associates, Nathan—well, that's not his real name, but even Nathan didn't know that this mission was insanely dangerous.

He just thought it was a regular mission we all do.