Leo, Prince of Nohr

When Leo attacks, the defending player puts the top 4 cards of their library into their graveyard.
When a land card enters your opponents graveyard add a mana of any color to your mana pool.
When a creature card enters your opponents graveyard, create a 4/4 black/blue Faceless creature token.
When a non-creature spell enters your opponents graveyard, Leo gets +2/+2, Indestructible, Hexproof and Lifelink.