The Iron Throne

Whenever a player gains control of The Iron
Throne or when it enters the battlefield, that
player becomes the monarch and gains 4 life.
{4}: Gain control of The Iron Throne. Any player
may activate this ability and can only activate it
if a creature left the battlefield this turn.
"Any man who must say 'I am the King' is no true
king. I'll make sure you understand that when I've
won your war for you."