Yu Narukami, The Fool

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.