Maou Gakuen no Hangyakusha

Synopsis:

All that humanity is is a slave to the wicked race. Morioka Yuuto, a typical high school student, was selected as a contender for the position of next devil king. Other students treated him with contempt once he transferred to Ginsei Silver Star Academy, the academy for the devils. I will make you the demon king, I promise. Make me your retainer because of this. Yuuto's life and the world were altered when he met Himekami Lizel, a beautiful devil. By making skin contact with his lady retainers, he could absorb magic power indefinitely and learn any type of magic quickly. Only the human Yuuto was allowed to use that unique power, which the devil species lacked. To become the demon king of justice, the human who was elected as a candidate faced up against the most powerful devils.