Akuma-kun (ONA)

When Mr. Satou, a company employee at the world's largest electronics company, is called upon by his boss to tutor his only son in exchange for a high ranking position within the organization, things couldn't have been peachier. At least, that's what he thought...

Little did he know that his student was Ichirou Matsushita, a young boy with the mind of a genius and a terrifying hidden agenda. It doesn't take long for Satou to realize that he is the second home tutor in as many weeks that has been sent to teach the little boy. What's even more unnerving is that the previous Tutor's whereabouts appear to be a mystery...

The little boy's true identity is revealed when he puts Satou under a curse, turning him into a lizard man and making him one of servants. Little Ichirou Matsushita is none other than "Akuma-kun" boy genius and master of black magic. His goal? To open the portal between hell and earth, summon forth hell's most powerful demons, and enlist their help in taking over the world!

(Source: MAL)