The kind predator and Royal Prey

in this world, Witches and other magical beings exist, all possessing extremely strong powers, the Seven Wonders being the strongest of them all. All beings rule over a kingdom, the kingdoms ruled by the wonders having the largest populations. An excorcist family, thought to have gone extinct, send out some o their children, believing enough time has passed, and that it was time to put an end to the Witches and magical beings once and for all.

when kou minamoto is assigned to kill one of the Seven most powerful, what will happen?

will he be able to kill him? or will he spare him?

Mitsukou Au!!

Wanted to give a better description but it's mostly already explained in the prologue!

This will contain:
Angst
Drama
Discrimination
Peer pressure
Heavy angst
Suicidal thoughts
Suicide attempt