Black is the primary color of sacrifice, so it is trivial to sacrifice your creature for value while gaining life and burning opponents with Vengeful Bloodwitch
Unfortunately the ability can only be activated on your turn, but with the aggressive leanings of this commander I think you want to be going for the acorns anyway
This is pure value in decks that thrive on landfall or bird creature ETBs
Instant Color tag templates(None) Undying Malice Until end of turn, target creature gains "When this creature dies, return it to the battlefield tapped under its owner's control with a +1/+1 counter on it." Instant Color tag templates(None) Vampiric Tutor Search your library for a card, then shuffle and put that card on top
And would a deck built post-FIRE design last longer
Its very powerful, its only two mana, and you should be running it in any deck that has Green and at least one more color in it