Seitarou Yagiri

Seitarou Yagiri is Namie and Seiji's uncle.

Charateristics
Not as much shown but he wears a lab coat and has silver hair.

Dollars/ Mia Harima Arc
He shows Namie the head that was found in Ireland.

Adabashi Arc
He demanded Shingen to give Celty's head to him which is revealed in a flashback. Shingen refuses. So Seitarou said that he'll mess with Shinra if Shingen didn't give him the head. Shingen did give him the head. At the end of the novel he is warned to not go near Yadogiri Jinnai.