Hitotsumi is a Summer Makamou with illusionary powers that serves an Oni Hunter, able to assume the form of teenage girl. He devoured Kabuki once he failed his masters. After his master died, Hitotsumi battled Hibiki before being subjected to all Onis' Onigeki attacks before Hibiki finishes him off.
Hitotsumi's design is based on Majinsai, the lead antagonist of Henshin Ninja Arashi.
Kamen Rider Decade: All Riders vs. Dai-Shocker
Hitotsumi revived and join Dai-Shocker army.