The Obsidian Goddess, Kokuyō no Megami, is an elusive goddess hunted by the Obsidian Eight organization. She appears as a woman possessing distinctive white hair and violet eyes. This entity exists as a concealed presence hidden within the body of the protagonist, Musashi, evading external detection.

The Obsidian Eight actively pursues her capture due to her critical function as a "compass" capable of revealing the location of divine treasures. Their objectives include preventing her control by Bushi warriors while simultaneously ensuring the survival of the Kishin demons, with whom they seek coexistence.

Her connection to Musashi involves generating black stones, similar to those projecting holographic communications during Obsidian Eight gatherings. These stones facilitate the organization's coordination efforts against her.

The Obsidian Eight employs operational strategies including deploying undercover members to capture her, underscoring her significant value to their overarching plans.