Enigmatic

Enigmatic Villains are characters whose origins are shrouded in mystery. They often appear out of nowhere or have extremely vague pasts, and give little clue about their identity. Their name, their true nature, or even their motives are often ignored.

Some enigmatic characters could also be heroes as much as villains.

They are often dangerous, intimidating, and unapproachable because they are unpredictable, hard to understand and (most importantly) nobody knows how to defeat them. Even when they are defeated or killed, enigmatic villains leave behind many unanswered questions.