The Priestess

"Riko"

- Maybe Shrine Maiden is a code-name? It's something that comes up in Orth fairy tales

The Shrine Maiden is a mythical figure thought to communicate with incarnations of The Abyss and warn of impending danger. Cravali and his companion Tepasté are the only individuals known to have communicated with this person. She is the presumed leader of Under Nest. According to Srajo, the Shrine Maiden cannot move past the "the final boundary" and thus relies on followers such as Tepasté to gather information.

Nishagora's questioning of Team Riko suggests that the Shrine Maiden is either a White Whistle herself or has one at her command. Srajo explains that Hariyomari's Song is the product of a collaboration between the Shrine Maiden and a delver.