Master Yen Sid

Jodah, the Unifier
Legendary creatures you control get +X/+X,
where X is the number of legendary creatures you control.
Whenever you cast a legendary spell from your hand, exile cards from the top of your library until you exile
a legendary nonland card with lesser mana value. You may cast that card without paying its mana cost. Put
the rest on the bottom of your library in a random order.