OVA
Description
Mai Amatsu is one of the two titular protagonists of the anime. She is the younger of the Amatsu twin sisters, with her older sibling being Ai Amatsu. The twins are students at Tenjin Girls High School and are the latest in a long lineage of female warriors and virgin priestesses. Their ancestry traces back to a union between a fisherman and a celestial being, an angel from the Buddhist tradition. This divine heritage is the source of their responsibilities and powers.

Physically, Mai is distinguished from her older sister by her shorter brown hair, which is cut to shoulder length. She has purple eyes and the appearance of a teenage girl, consistent with her status as a high school student. As a pair, the twins wear school uniforms as they balance their academic lives with their secret duties.

Mai, alongside her sister Ai, is charged with a critical mission: to guard a young half-demon named Onimaro. Onimaro is a distant relative who stands at a crucial crossroads in his development, possessing the potential to become either a great warrior of light or a devastating Demon King who would tip the cosmic balance toward evil. The forces of darkness, including demonic minions sent from the Pleasure Underworld, seek to capture and corrupt Onimaro to ensure his path leads to destruction. Mai’s primary role is to battle these lascivious forces and protect Onimaro from falling under their influence.

In her duties, Mai often works closely with her immediate family. Their grandmother, Genshu Amatsu, is a matriarchal figure who oversees the twins and their mission. They are also aided by Dekunobu, a guardian appointed to watch over Onimaro. While Mai and Ai are tasked with protecting Onimaro, his persistent presence often frustrates the sisters, complicating their efforts as he follows them in their daily lives.

The story presents Mai as a proactive protagonist, engaging directly in combat against demonic invaders. Her abilities are rooted in the ancient, mystical techniques passed down through her family line of warriors. As a virgin priestess, her spiritual purity is integral to her power to fight the forces of sexual perversion and corruption. The narrative follows her as she confronts a series of surreal and extreme demonic entities, struggling to prevent Onimaro from choosing the path of darkness and becoming the next Demon Lord.