The Defector is at its most basic a character who switches their allegiance at some point during the story. Unlike The Mole, their former allegiance was genuine up until that point.
Their motives for doing this can vary considerably. It could be the result of moral differences with their former compatriots, done for the sake of one's advancement, or even because the character is simply a Wild Card. It can be part of a Face–Heel Turn or Heel–Face Turn if the character went from a clearly good side to a clearly evil side or from a clearly evil side to a clearly good side, respectively.
There is some overlap with Screw This, I'm Outta Here, though that can also apply to characters who simply abandon their post without necessarily joining another faction.
Super-Trope to:
Please only put examples here that don't fit into any of the subtropes listed above.
