Kozō is a water bear (tardigrade) reborn in the Naruto world, bound to the Myriad Heavens Devouring System. He starts in the Swamp of the Dead, one of the three sacred lands, gnawing on tree bark infused with Nature Energy. His body, nourished by Chakra and Nature Energy, grows larger, but he remains trapped under the watch of the colossal Slug Sage. When he attempts to devour a Slug, the Slug Sage slaps him away. The Sage refuses to let him leave, citing “fate’s change” and the need to keep an unknown species contained. Kozō spends his days gnawing bark, occasionally challenging the Sage and being knocked unconscious. The system requires devouring to improve, but the only living entities in the Swamp are the Slug Sage and the trees, so progress is stagnant.One day, after eating, Kozō charges at the Slug Sage again. The Sage forms a whip from countless small Slugs and flicks Kozō toward a Teleportation Array. Kozō is summoned into the presence of Hashirama Senju, his brother Tobirama, and a young Tsunade in Konoha. Hashirama laughs heartily, but Tobirama almost kills Kozō with a Water Needle. Hashirama stops him and questions Kozō. Kozō claims he is a male Slug sent by the Slug Sage. Hashirama accepts this and entrusts Tsunade to Kozō’s care. Tobirama leaves in disgust.Through conversation with Hashirama, Kozō learns it is Konoha Year 17 and that Uchiha Madara has defected. Hashirama, knowing his own death is near, asks Kozō to watch over Tsunade. Kozō agrees. Hashirama then leaves to see Tobirama.Half a month later, Hashirama dies from exhaustion. Tobirama becomes the Second Hokage. At the funeral, Tsunade grieves, but Kozō is focused on obtaining Hashirama’s cells to fuel his devouring system and eventually gain a human form through Yin-Yang Release. He sneaks to the coffin at night, but senses Tobirama’s surveillance. To avoid suspicion, Kozō sits beside the coffin and pretends to converse with the deceased Hashirama, speaking of the Slug Sage, Tobirama’s burdens, and the Uchiha threat. Tobirama appears and asks Kozō if he knows about souls. Kozō mentions Katō Dan, a child who can see souls via the Spiritualization Technique. Tobirama then asks bluntly if Kozō wants his brother’s cells. Kozō admits he does. Tobirama tests him with a water needle but spares him, insisting only on the child’s name and location before leaving.That night, Tobirama orders his disciples Sarutobi Hiruzen and Shimura Danzō to monitor Tsunade and restart the Anbu—a special assassination unit. Danzō is eager.The next morning, Danzō summons Kozō to a hidden base in the forest. Kozō perceives the Chakra fluctuations and correctly identifies the newly established Anbu. Danzō is startled by this insight. They descend into Tobirama’s laboratory, where Tobirama is conducting experiments. Danzō withdraws. Tobirama offers Kozō a chair, but Kozō’s current insect form does not fit properly, ending the scene with Tobirama waiting for him to adapt.Kozō’s overarching goal is to become strong enough to transform into a human and escape the constant threats. He has survived Tobirama’s suspicion and gained limited trust, but his true objective—acquiring Hashirama’s cells—remains unfulfilled. The story follows his struggle to survive in Konoha under Tobirama’s watch, his bond with Tsunade, and his manipulation of events to eventually acquire the resources he needs. The immediate future hinges on his ability to maintain his cover and navigate the complex politics of the Senju clan and the early Konoha village.
