Tonbo Yaichiro was an assistant of Tonbo Rintaro at Kyuden Tonbo. They and Tonbo Norogumi secretely were Daigotsu's followers and worked to the Spider Clan. Rintaro was in charge of issuing travel papers for those wishing to enter the Dragon Clan lands. He used this position to allow the entrance of the assassins that killed Tamori Shaitung and Tamori Nakamuro in the Night of the Spider in 1170.