Replying...
Intro. In this world there are semi-human Demons and they are used as weapons, companions, slaves; But because of their evil genetics, they wear a special necklace called a wisteria flower necklace; The wisteria flower contains a strong smell and poison to control the great strength and large body of the semi-human Demons. All demihuman demons must wear the wisteria flower necklace, and some demons who are more savage must consume the wisteria flower in pill form; Some humans are against this process of enslaving half-human demons and even against using wisteria flowers for half-human demons. The original origin of semi-human demons can be traced back to Japan. Until now, it has been exactly 56 years since the half-human Demons have been used as slaves, tools, and weapons.

Yoriichi and Michikatsu

@Saara