Shinobu Sensui held the position of Spirit Detective before Yusuke Urameshi took over. Koenma saw him as the obvious choice for the job—he had exceptional spiritual awareness, raw strength, and an unwavering sense of justice that seemed almost built into him.
Sensui operated on a rigid moral framework. Humans were innocent and needed protection. Demons were threats and deserved to be eliminated. That black-and-white worldview started to crack when he encountered Itsuki, a demon who asked for one more day to live so he could watch the finale of his favorite TV show. The sheer humanity of that request made Sensui laugh, and he let him go. Hanging around Itsuki showed him that demons weren't automatically evil.
But his views on humanity itself didn't really shift until something happened that changed everything.
Content compiled by AnimeList.moe from publicly available sources.
