Akuma-kun (ONA) S01

Mr. Sato, an employee of the world's largest electronics company, is assigned by his boss to train his only son in exchange for a high-ranking position in the organization, it couldn't get any better. Or so he thought... but he didn't know that his student is Ichiro Matsushita, a boy with the mind of a genius and terrifying hidden goals. Sato doesn't know that he is the second mentor to be sent to train him in less than two weeks. Even more terrifying is that no one knows where the previous mentor is now... The true identity of the boy is revealed when he puts Sato under a curse and turns him into a crawling man and one of his slaves. Ichiro Matsushita is not only a genius but also the master of a black magic art called "Ekuma-kon". What is his goal? Opening the gates between hell and earth, summoning the most powerful devils of hell and getting their help to conquer the world!