Heroes who get possessed or brainwashed by the villain. Possession means that the host's body was taken over by a demon or some other form of evil spirit, and brainwashing simply means that they were hypnotized, mind controlled, bitten by rabid animal, etc. Alternatively, they can still be good and possessed or brainwashed at the same time, but they are mostly controlled by evil forces.

Note: Don't be confused with villains who are either possessed or brainwashed, unless they've turned to the good side.

Some Pure Good heroes can fall under this category instead of being fallen or corrupted to the dark side or on & off (e.g. Buzz Lightyear (Toy Story) and Milla Basset). Pure Goods never WILLINGLY corrupt themselves, of course.