Isshiki Ōtsutsuki

Isshiki bore the telltale features of the Ōtsutsuki clan, including pale skin, and a long, curving horn which grew from his left brow and wrapped around the back of his skull before jutting outward from his right temple, resembling a crown. His right eye was a Kokugan, while his left eye was a Byakugan. He bore matching tattoos on his chest and back: on his chest was a vertical column of six magatama or tomoe topped with an emblem resembling a black mallet across his chest, and on his back was a vertical column of six smaller black mallet emblems. His hair, right eyebrow, and goatee were pale blue trimmed short with unusual alternating zigzag patterns resembling the hair parts worn by other members of his clan, while his fingernails and toenails were painted in deep black. Isshiki preferred to dress in an elegant, slim cut, white long-sleeved tailcoat with maroon lining and cuffs and an oversized collar that folded back upon itself over his bare muscular torso, over a pair of baggy black pants that often covered his bare feet. The coat was embroidered with patterns matching his tattoos, with vertical columns comprised of eight magatama designs on the sleeves, and a similar pattern on the back, with the second magatama replaced with the black mallet emblem.

Long 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. Eventually, Isshiki found Kawaki; after Delta tested the boy's blood as a viable candidate to be a vessel in the anime. Jigen approached Kawaki's abusive father with a large sum of money, to buy the boy for his plans. After taking custody of the boy, Isshiki introduced Jigen as his new father and reassured him. Eventually, Isshiki found Amado Sanzu, a scientist who endured several failings to revive his daughter Akebi. Recognising the man's talents, Isshiki offered him a place in Kara with the promise of reviving Akebi through the Chakra Fruit. Upon joining Kara, Isshiki had Amado use the remains of Shibai Ōtsutsuki to implant various powerful abilities into the members of Kara. He also had Amado modified Isshiki's vessel with Scientific Ninja Tools, the two attempted to transfer Kāma to Kawaki, Code and thirteen other boys in an experiment. Kawaki was the only success, while Code gained an incomplete White Kāma and the other thirteen perished. Despite promising him safety, Isshiki put Kawaki through gruelling training to master the Kāma and would constantly berate him as only having value as a vessel, striking the boy whenever he questioned him. Meanwhile, Code was recruited as his most loyal subordinate. At some point, Amado presented to him several cyborgs he had modified to secretly bring down Jigen, under the pretences of being useful for the sake of Kara's plans; however as their combat abilities exceeded Jigen's, he ordered Amado to dispose of them to not undermine his position as leader and ordered Boro to get rid of them, not knowing that Boro had actually hidden them all in his cult. In the anime, another Inner Ōga was enhanced to help Amado with his research on the human heart. When she attempted to study Jigen's, he considered it treason, and destroyed a portion of her brain before she escaped.