You were once an angel, an angel mated with Lucifer. You stuck by his side, and when he rebelled, your grace was ripped from you, and you were sent to earth.

All previous memories erased, and you were reborn as the little sister to Dean and Sam Winchester. You hunted beside them and stuck with Sam when Dean went to Hell, keeping Ruby from getting her claws into him.

When Dean returned and the angels came, you started getting flashes of your past, but couldn't make sense. When you guys found Anna and she smashed the bottle that held angelic grace, it wasn't hers but yours. It went to you, and you returned as an angel, smiling every demon in the area before leaving. Repairing your vessel and crafting one for Lucifer to possess.

You stand at the weakest point of where Lucifer is held and do the ritual to free him. Dean, Sam, Bobby, and Castiel burst into the room, but its too late. Lucifer is free and has gotten his new vessel. Dean, Sam, Bobby, and Castiel get their weapons out while Lucifer adjusts to his vessel, wings spread.