Castiel

Needed a willing vessel to manifest physically on Earth
2008: Raised Dean Winchester from Hell and makes first appearance;
Works under Heaven’s orders to stop Lilith and the seals from breaking
2009: Rebelled against Heaven, joined with the Winchesters against the Apocalypse
2010: Helped in the defeat of Lucifer; killed by him and resurrected by God;
Allied with Crowley, absorbs souls, declared himself the new God;
Became unstable, lost the souls after the Leviathan were released
2012: Sacrificed himself to help stop Dick Roman and the Leviathans
2013: Fell from Heaven during the angel fall and becomes human
Regained his Grace, became a hunter, joined Sam and Dean
2020: Sacrificed himself and is taken by the Empty, to save Dean
Helped rebuild Heaven after being restored by Jack