Hamartia
(n.) A flaw that leads to a character's downfall
Examples of Hamartia
Hamlet falls from his high ranks and faces death due to the fact that he was a procrastinator.
Batman was naive to the fact that the Joker would make Harvey Dent a bad person, so Batman had the take the blame for things Harvey did which led to everyone not looking up to Batman anymore and he was in hiding for 8 years.