Kumoshichi

Yuki's friend, whom nobody except Yuki can see. The real Kumoshichi was Shikiji, a man who Yuki knew about fifteen years ago. However, he attempted to snap Yuki out of his self-destructive haze by tricking and goading him into a life-or-death fight, and forcing Yuki to stab him in self-defense. Yuki blocked out the entire incident, and unconsciously created a Yoi in Shikiji's form. After this, Kumoshichi followed Yuki everywhere and often would give him advice.

Yuki was shocked when he realized that he had killed the real Shikiji, and that his longtime friend was actually a Yoi he had created. When the horse/dragon Quetzl began running wild, Kumoshichi merged with him and successfully calmed the Yoi until it was no longer dangerous. As a result, Kumoshichi only existed after that as a part of Quetzl - a talking horse.