Drentor, Krasis of Tarkir

Trample, hexproof
Drentor, Krasis of Tarkir gets +1/+1 for each instant or sorcery card in all graveyards.
Partner (You can have two commanders if both have partner.)
Whatever this thing is, it doesn't seem capable of much speech, but it insists it's name is Drentor. It says it's searching for someone named Momir Vig.