Ayato, Blade of Serene Water

Serenity - (Effects, spells, abilities and rules cannot
make you discard cards.)

You may look at the top card of your library at any
time.

Twice per turn, you may cast a spell from among
cards in your hand or from the top of your library without paying its mana cost if its mana value is
equal to or less than the number of cards in your
hand.