The Lich King

Can't be the target of spells or abilities.
When the Lich King enters play, lose half
your life, rounded down. Gains +X/+X where X
is this amount.
You can cast creatures from your graveyard.
During each players upkeep, they sacrifice
a creature. If they can't, they lose 3 life. If you
sacrifice the Lich King, you lose the game.
{t}{b}{b}{b}: Exile target creature.
In the end, you will all serve me