Ei is a centuries-old vampire hunted by factions across a flooded post-apocalyptic world, his youthful guise belying the ancient blood that fuels his immortality. He controls vital resources crucial for survival following the Antarctic thaw’s catastrophic flooding, operating within a clandestine group that consumes other lifeforms to endure—a grim necessity consumed by their quest to locate a mysterious "help" for their species’ continuity.

His existence draws relentless threats from those coveting his unique biology, forcing him to navigate the labyrinthine floating cities like Galacius, where survival hinges on ruthless trade-offs and scavenged scraps. A weathered violin remains his constant companion, its retrieval prioritized in every skirmish—a quirk that unmasks his true nature during clashes.

Antagonists like Harris stalk him, intent on exploiting vampirism to resurrect collapsing humanity. Yet Ei reluctantly forges alliances, including a pact with a shrewd, bespectacled wanderer, their uneasy partnership evading capture while peeling back layers of a cloning-driven dystopia. Here, female extinction has birthed synthetic replication cycles, deepening ethical fractures over resource hoarding and humanity’s devolution.

Ei’s choices spiral around survival’s primal calculus and the fragile search for purpose in a disintegrating world—each step shadowed by the paradox of preserving his own existence while confronting the cost of humanity’s desperation.