Whenever another creature you control dies, you get an experience counter. At the beginning of your end step, choose target creature card in your graveyard. If that card's mana value is less than or equal to the number of experience counters you have, return it to the battlefield. Otherwise, put it into your hand.

Vigilance This creature gets +1/+1 for each creature card in your graveyard. {T}, Sacrifice another creature: Search your library for a land card, put it onto the battlefield tapped, then shuffle.

At the beginning of your upkeep, if you have four or more creature cards in your graveyard, you may return target creature card from your graveyard to your hand.