Liliana, Grave Waker

At the beggining of your end step, if there has not be any card putted into your graveyard, put the top three cards from your library into your graveyard. Then, if there are five or more creature cards in your graveyard, sacrifice Liliana, Grave Waker, and create a black legendary planeswalker token named Liliana, the Necromaster.
When Liliana dies, return target creature with converted mana cost 3 or less from your graveyard onto the battlefield.
After the Gatewatch had fallen apart, Liliana retur