Tears to Tiara

The Holy Empire's expansion eventually reaches the small island of Erin, home to the Gael tribe, leading to a struggle for control. Riannon, a Gael priestess, is kidnapped to be offered as a living sacrifice to the demon king Arawn, and is later rescued by her brother, Arthur. Arawn, the demon king, appears to them as a grey-haired man and pledges his power to the tribe, joining Arthur and Riannon in their fight against the Empire.