Hyped up by herself and Kicchou Yachie to be the reincarnation of Sun Wukong, Biten is a sarugami who works for the Kiketsu Family as part of their operations to take over the surface world. In reality, as with Mitsugashira Enoko and Tenkajin Chiyari, she is a spy whose true allegiance lies with Nippaku Zanmu. She was tasked with sabotaging the Kiketsu Family's invasion plans from within by playing them for time as part of Zanmu's gambit to prevent a surface war. At the end, she decides to stay with the Kiketsu Family for real after feeling sorry for Yachie.
