Yakumo Katou, Ao Ninger
Full Name: Yakumo Katou
Ranger Designation: Ao Ninger
Gear: Ninja Ichibantou, Gamagama-ju, Karakuri Hengen
Otomonin: Dragomaru, Seiryumaru

Yakumo has lived most of his life abroad and was learning European magic in England when he was called back. He has cool demeanor and somewhat arrogrant. He has a quick temper and stubborn. One of Yoshitaka Igasaki's successors, Yakumo was one of his grandchildren chosen to become the Nin Ningers. He was called by Tsumuji Igasaki, his uncle and Takaharu and Fuuka's father to return to Japan. Out of his cousins, Yakumo is a quick-learner and can master ninjutsu quickly than the others, claiming it easier than magic and at first had no interest in it. He had developed a rivalry with Takaharu, he decided to compete with the others to inherit his grandfather's title as the Last Ninja. As Ao Ninger, the Cool Ninja, his signature attack is the Ninja Dragon Slash.

After the final battle against Gengetsu Kibaoni, Yakumo returns to his magic school in England and introduces the combined techniques of ninjutsu and magic, though still has a long way to go teaching the British wizards.