La Blue Girl

La Blue Girl (淫獣学園, La☆Blue Girl Injū Gakuen La Blue Girl, lit. "Lewd Beast Academy: La Blue Girl") is an erotic anime and manga series by Toshio Maeda.

Plot
The story involves various ninja clans in a constant state of war with one another. The female protagonist is Miko Mido, a young ninja-in-training and the next leader of the Miroku ninja clan. This clan has control over the Shikima, a perverted race of sex-hungry demons led by Miko's father, the Shikima Lord. However, when thieves steal the magic compact that grants the clan this power, Miko has to fight the Shikima, utilizing her "sexcraft" ninjutsu in order to save the world. The Shikima live in a parallel dimension called the Shikima world, and one must perform specific sexual rituals in order to travel there.