Multiple Personality Characters

Ever seen a character that can switch up personalities? Is it in their nature or is there really another being living inside of them waiting to come out? This is the club for them. Let us list all these wonderful characters here. **THERE MAY BE SPOILERS*** Once we have enough we can compare how greatly they can shift. Note it's not just them suddenly snapping or something but it is like an actual change that can happen frequently or is at least known to happen frequently by others observing them. For a technical partial definition: "a condition in which a single person displays multiple distinct identities or personalities, each with its own pattern of perceiving and interacting with the environment. The diagnosis requires that at least two personalities routinely take control of the individual's behavior" (from Wiki)