Have you considered adding something like Grave Pact?

Leyline of the Void can help get your devotion up

I'd advise going down on discard and up on land. I'd also advise finding space for the 4th Gary and possibly some copies of Fatal Push.

Thanks for the feedback everyone, I have taken your comments into consideration.

Lol devotion black deck without Erebos, God of the Dead. Put the card in or change the name of the deck. Otherwise I like it.

Good build. Brutal and efficient.

I upvoted and wrote this comment before even looking at the name, because Typo-0. Don't know if you even know what that is, but you do now. Okay, gonna actually look at the deck now. Might have an actual comment afterwards.

Yes I like Type O Negative.

Ok, for the real comment.

You have a very good balance here, and I wouldn't want to mess with that. However, I would use Liliana of the Dark Realms over Liliana of the Veil. You have plenty removal and discard, so only LotV's Ult seems like it adds anything. Albeit, it's a great Ult, I will admit.

Furthermore, if you included LotDR, you could include a couple Consume Spirit pretty easily. And, since you're running 8 fetch lands, you could maybe even throw in a one-of Goblin Charbelcher, just because.

Also, also, mad props for Gatekeeper of Malakir. I don't see that in nearly enough mono-black decks.

Liliana of the Veil works with Bloodghast and to a lesser extent Relentless Dead.