Very good combo you could even go black white with it and use day of judgement instead of lifes finale. Lifes finale is a little better though cause you can search your opponents library for 3 creature cards and put them into your graveyard then you sacrifice grimoires of the dead and now you have a massive army.
{Grimoire of the Dead}
{Life's Finale}
{Day of Judgement}
This a very cool combo. I used a similar combo using {Liliana Vess}'s last ability and Day of Judgement. What else makes this combo excessive is {Fresh Meat}, a commonly suggested card of late.
And don't forget {Buried Alive}
{Damnation}, {Mutilate}, {Decree of Pain}, unless you are limited to Standard, you can do this mono-black.