Rasha or Rasha the Imp is the name of the lesser demon Reika Kitami implants inside Academy student Taki Minase's body as a way of tempting him to her will. The entity is featured in both the first game and first anime series based on it but is only named by name in the former.
The demon is a servant of Kitami and a kind of incubus, highly skilled in the art of lust. Its mark is scratched into Minase's body by Kitami in a triangular shape that swells up when the demon is called.
The imp is given to Minase when he is confronted by nurse Reika Kitami in the basement of his school. She seduces him and they have sex. Afterwards, the boy pledges his loyalty to the witch and she grants him Rasha's power.
The powers of the demon allow Minase to use several abilities. He first unwittingly puts a strong arousal spell on his cousin Yukiko by merely rubbing her breast, causing her to frantically masturbate.
Later he casts a powerful purple orb to magically stun his friend Kurumi Imari. However, in the brief time it takes for him to cast the spell, Imari is able to slap Minase in the face, seemingly nullifying Rasha and bringing the boy back to his senses.
In the first game, even more of the demon's powers are revealed. Minase shatters a porcelain cup on his desk by just thinking about it and later tests out his abilities on school bully Shinjou. In this instance, he has the demon take control of the boy and forces him to jump off the school roof.