"How dreadful!" cried Lord Henry. "I can stand brute force, but brute reason is quite unbearable. There is something unfair about its use. It is hitting below the intellect." ~ Oscar Wilde - The picture of Dorian Gray
Even if ENTJs are the opposite of evil, they will defy anybody who pressures them to live their life on anything but their own terms or have certain values for anything but their own
reasons. They are a lot like INFPs in that sense, but they just aren't afraid of people or
the situations they get boxed into.
The most evil villain I have ever seen in popular culture was an INFP named Johan from the Anime "Monster". He was incredibly charismatic and kind on the surface, but he could mindfuck who ever got in his way. Maybe the fact that his appearance contrasted to sharply with his motives made him seem more evil than an XNTJ like Lord Voldemort.