Sanjo Takii is a member of Shirahama Taiyou's Monster Strike team, which operates at the same school as main protagonist Ren Homura and his companions. This four-member team consists of Noda Akane, Shirahama Taiyou, Nikaido Jun, and Sanjo Takii. Sanjo Takii's documented appearances are limited to this team affiliation. He is first observed in Episode 10, appearing as one of three cloaked figures accompanying Taiyou on a rooftop.