evil genius

noun2

1. •
   An intellectually brilliant person who excells at using his or her mental abilities for negative or harmful ends; especially a criminal mastermind.
2. •
   The spirit each person is believed to have in attendance, according to certain religious or mythological traditions, which tries to negatively influence him, and is opposed by his good genius; loosely, someone who is a bad influence.

   • He could in nowise comprehend it; but, taking it with other previous circumstances, he could not get quit of a conviction that he was haunted by some evil genius in the shape of his brother […]. — 1824