Isshiki Ōtsutsuki (大筒木イッシキ, Ōtsutsuki Isshiki) was a member of the Ōtsutsuki clan’s main family and the leader of Kara.

A thousand years ago, Isshiki came to Earth alongside Kaguya with the objective to plant a Tree to harvest its Chakra Fruit. While Kaguya, being lower-ranked, was planned to be sacrificed to create the Chakra Fruit, she instead turned on Isshiki, leaving him on the verge of death after destroying Isshiki’s lower half. Encountering Jigen and not having the strength to implant a Kāma on him, Isshiki devised a desperate plan and shrunk himself to enter the monk’s ear in order to survive his injury by absorbing Jigen’s nutrients. Through time, Isshiki came to control Jigen’s entire body and embed a Kāma onto his host.

Upon the formation of Kara, Isshiki through Jigen became its leader and acquired a new Ten-Tails seedling; the Inners collectively agreed on obtaining the Chakra fruit by cultivating a new God Tree huge enough to devour all life on Earth. With Kaguya’s betrayal and eventual sealing leaving Isshiki alone, he was left with no other option but to use himself via Jigen as the sacrifice for the Ten-Tails, in order to make it bloom into a God Tree. Passing on reviving himself through Jigen as his body would die within a few days as it wouldn’t bear his chakra, he instead opted to cultivate Jigen’s body as much into an Ōtsutsuki as possible to be fed to the Ten-Tails for its growth. With this intent, Isshiki began preparing for a new vessel to embed another Kāma seal once he fed Jigen and himself to the beast.