Arc, the Decimator

-1: Sacrifice a creature. Then each player sacrifices a creature. Put a loyalty counter on Arc, the Decimator for each creature sacrificed this way.
-13: Each player sacrifices each creature he or she controls. Put all creature cards form all graveyards onto the battlefield under your control.
: Arc, the Decimator can be your commander. As long as Arc, the Decimator is in your command zone, Eldrazi spells you cast cost {1} less t cast.