An immortal entity arrives on Earth as a shape-shifting orb, mimicking a rock, moss, and a dying wolf before meeting a white-haired boy in a frozen tundra. When the boy dies, the entity adopts his form, embarking on a transformative journey to cultivate human emotions and identity through encounters with others. A girl named March introduces it to language and names it, her sacrificial death imprinting grief upon the entity, which then mirrors her appearance. Guided by an elderly woman, Pioran, it hones speech and social skills while battling parasitic Nokkers that drain its forms and memories. During this time, it claims the name Fushi and unlocks powers to materialize objects. In Takunaha, Fushi bonds with Gugu, a disfigured boy whose selfless death cements Fushi’s grasp of mortality and loyalty. Captured on Jananda Island, Fushi clashes with Hayase, a warrior fixated on dominating him. Her lineage later spawns a cult venerating Fushi, complicating his retreat from humanity. Awakening after six centuries into a technologically evolved world, Fushi confronts resurgent Nokkers—now microscopic puppeteers—led by Hayase’s descendant. Resurrecting fallen allies, he wrestles with the ethics of manipulating human fates. His creator, the Beholder, unveils Fushi’s destiny as the world’s successor, granting omnipotence he refuses to retain bonds with humanity. Over millennia, Fushi evolves from an indifferent observer to an empathetic guardian, mastering resurrection and reconciling eternal life with humanity’s fragility. Bonds with allies like Tonari, Bon, and Mizuha test his resolve to protect without overriding free will, culminating in a vow to coexist with Nokkers while shielding humankind.