|“||Your father... was seduced by the dark side of the force. He ceased to be Anakin Skywalker and became Darth Vader. When that happened, the good man who was your father was destroyed.||„|
|~ Obi-Wan Kenobi explaining Vader's origins.|
Many heroes walk a thin line between good and evil, indeed many heroes have fallen into despair, rage, or even madness, and once proud heroes descend further into the path of evil, often fighting against people they once protected or fought alongside. Originally protagonists or somewhat good guys, these villains turn evil due to events in their lives, such as being corrupted by another villain, their desire for revenge, a failed love relationship, or even betrayal from the good side to the dark side. A Hero turned to the Dark side is usually the end-result of a protagonist exposed to a Corrupting Influence, Brainwasher, Posessor and ocassionaly a Charismatic Villain or Extortionist or Blackmailer.
In some case, heroes that turned to the dark side tended to be From Nobody To Nightmare, had these heroes are used to be a harmless individual that unlikely shows any sign to become a fearsome villains.
EXTREMELY IMPORTANT : Tragic villains do NOT automatically mean that they are heroes turned to the dark side. This category is meant for villains who used to actively work for the good side.