Kozuchi

His face carried such a likeness to Boruto Uzumaki that a fading Onoki once mistook the two for one another. Kozuchi was a short child with pale skin, dark blue irises, and jet-black spikes whose fringe fell to either side of his features. For clothing he favoured a red shirt layered beneath a grey vest, matched with grey trousers.

Only glimpses of the boy ever surfaced, yet each showed a cheerful, high-spirited child whom Onoki praised as unusually clever. His devotion ran in two directions, toward the grandfather he adored and toward Iwagakure itself. Ambition pointed him straight at the office of Tsuchikage, and he carried the village's Will of Stone as his creed, meeting every trouble without flinching. That same boldness had a darker edge. He badly misjudged how capable he really was, and the overreach ended his short life.

Once Onoki set aside his leadership and retired, the boy shared a home with him. His end came in a clash against rogue ninja who were plundering Iwagakure's guarded secrets. The loss sat heavily on Onoki, who blamed his own lessons about confronting problems head-on. Grief, joined with the memory of Kozuchi's wish to protect the peace, drove the old man toward a radical plan: cultivating artificial soldiers to fight in place of humans, work he pursued in secret using the remains of a White Zetsu. That research produced the Akuta and the Fabrication, which Onoki then unleashed to forcibly remake Iwagakure. When his creations spiraled into martial law, shame overtook him, certain his grandson would never have approved. Determined to atone before reuniting with Kozuchi in the next life, Onoki spent himself to end the threat.