Tap... tap... tap... tap... tap... tap... tap... tap... tap... tap... tap...

I remember the sound of my shoes which echoed in that long, treacherous, and nightmare-inducing hallway. That day I was headed towards my doom; the study hall were I met up with the Principal of my high school for a new mission.

For years I had been serving him and doing his dirty jobs, for one thing and one thing only; he promised to keep my sister Aoi in safe hands.

It was only for that very reason why I worked for him. It was because he had my sister and would threaten to hurt her and so...

We made a deal; I did the work and he'd keep my sister safe and that's all I needed.

My sister was the most important thing in my life.

At least that's what I thought before.

It all started on that very day the mission was assigned. At that time I thought I could do it, but something developed and in the end, it affected Aoi in a way I didn't think was possible.

When I walked towards the room, I never knew any of this was going to happen. That the mission I would be given would affect everyone I loved. If I had declined that mission, my sister would have died. If I didn't, she would finally be freed from his stained hands.

Aoi would be free but only because she was spared.

It was because the life of somebody else was to be taken.

And I was the one who would ultimately have to take it.