Akiba Girls(2004)

Akiba Girls is an adult anime series following Shindo Nikita, a hentai and H-game enthusiast who joins "The Alternative Trivia Research Club" seeking connection with like-minded people. His secret passion leads to sexual encounters within the club, but complications arise when he discovers that both of his foster sisters harbor romantic feelings for him. Caught between their affections and his own desires, Nikita must navigate the blurred lines between fantasy and reality while deciding who he truly loves. The series blends comedy with mature themes as it explores the protagonist's journey through otaku culture and unexpected family dynamics.