Imp's Mischief offers a rather unique effect in black - it can stop a counterspell or protect you from a Swords to Plowshares, Nature's Claim or Treachery. I think it's great and suggest you give it a try.
Personally, i'm not a fan of expensive removal like Silence the Believers. I prefer very cheap ones like Snuff Out, Slaughter Pact, Murderous Cut, Dismember and Ghastly Demise. Their upside is that you can keep casting your expensive haymakers every turn and still have access to removal (to stop that Brago, King Eternal or Rafiq of the Many before they can be equipped with Lightning Greaves or to get a Seedborn Muse off the table before it generates too much value).
Btw, if you are interested in a creature that allows you to interact with artifacts and enchantments, take a look at Steel Hellkite.

I got to say, I love this deck. +1!It really reminds me of my deck. deckhttp://tappedout.net/mtg-decks/we-all-must-make-sacrifices-1/

I would suggest three cards.Nantuko Husk for a sacrifice engine, which pairs well with both Gravecrawler and Genesis Chamber. Genesis chamber will create that many more tokens for you to sack.

Also, since you have so many ETB effect, I would also suggest Conjurer's Closet

This deck is a little insane. You really don't like people having life do you. Jeez! I hope I don't meet you when you have that deck at hand. 5 turn games are what will become of it. This a brilliantly horrible deck and I think you did well yet again no suggestions from me. Sorry.