The Harry Potter universe has shown that even characters that weren't considered villains could still have a mean streak tied to them. The best example of this was Argus Filch, who was Hogwarts' caretaker for decades. In that time, Filch was present for many important events, such as the reawakening of the Basilisk and the Battle of Hogwarts. But no matter the conflict, Filch always carried a surly attitude that made him infamous among the students of the school. And while he wasn't a villain, he was probably the closest thing most young students experienced during their time at the school.
Source：https://www.cbr.com/harry-potter-slytherin-greatest-enemy-mr-filch/
