Why: She falsely accused Arya's father, Ned Stark, of treason and had him arrested, which led to his execution on King Joffrey's orders.
Status: Alive, and sitting on the Iron Throne. And drinking lots of wine while standing on a giant map of Westeros. She has Zombie Gregor Clegane to protect her, but from what we saw in "The Spoils of War," she's not safe for long.