The series Inma Keiyaku Succubus (淫魔契約 サキュバス), typically recognized as a series of adult visual novels or interactive stories, centers on themes of supernatural contracts and the evolving relationships between human protagonists and succubi. The Visual Novel Database Character Relationships & Dynamics
For fans of this specific title, several other games offer similar themes of supernatural intimacy: Inma Keiyaku Sex Succubers
(The Greed / Business Succubus)
What starts as a transactional arrangement often evolves into genuine affection. The Conflict: Inma Keiyaku Sex Succubers