Webkokushibo is the first demon slayer to become a demon.
He became a demon in his early 20s and lived as such for additional 460+ years.
The relationship between yoriichi and michikatsu parallels the mythology of the shinto deities amaterasu and tsukuyomi ,.
Webkokushibo is a demon slayer who turned demon later in life.
The twin brother of yoriichi, his jealousy turned him into a loyalist of the evil muzan.
Webkokushibo is the only demon who is capable of using breathing abilities, and his blood demon arts provide extra skills and powers, which is why he still maintains the position of upper moon one.
Kokushibo’s main demon art is called crescent moon.