Kowaku looms among the Shichisei (Seven Stars), a cadre of elite Shikabane adversaries opposing the protagonists. Once a Buddhist monk, he underwent an unexplained transformation into a Shikabane, retaining remnants of his humanity through his vivid green hair and the ornate bead necklace encircling his neck. His cursed existence grants a twisted blessing: the power to manipulate his physical form, most frequently dissolving into a gaseous state to outmaneuver foes and amplify lethality in combat.

The necklace beads conceal his singular vulnerability—a preserved brain stored within them. During a climactic battle near the first season’s end, Makina unravels this secret, targeting the beads to dismantle him. His demise etches him as the inaugural Shichisei member felled permanently.

No expanded accounts of his presence in alternate narratives or media exist within the provided records. Prior to his undead state, his life as a monk stands as the sole documented fragment of his history, with the catalyst for his transformation shrouded in ambiguity.