The Semivillain

Not to be confused with the Antivillain, an antagonist who has heroic intentions and works towards them with malicious acts.

The Semivillain is a Villain-like character whose intentions aren't entirely villainous, but they do just as much bad as good if not more. The Semivillain might be ignorant to how they're hurting those they wish to help, making them less of an antagonist. But the reverse can also be true — the Semivillain can be fully aware that they're hurting people, but they rule their own intentions above their helpees because they sincerely want to lend a hand, even if that hand threatens to kill everyone in its path if it can't assist anybody.

An example of a Semivillain is one that wants to help their friend in a competition, so they severely harm all the other competitors before the game so then their friend would be sure to win. The friend doesn't want the help because it's dishonest to cheat. However, the Semivillain really wants their friend to win, so they ignore their plead to be fair in the competition.