Relentless Rats!?!?!?!?

I am putting together a rat deck. So far I have 22 relentless rats and 4 thrumming stones. Any ideas for anything else I could use in this deck that would be beneficial. I don't want to rely solely on the rats.

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Relentless Rats
Thrumming Stone

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I think the biggest threat to this deck is mass removal.  One Day of Judgment can really ruin your day.  How about a Patriarch's Bidding?

Maybe mana accel like Dark Rituals.

22 relentless rats
4 thrumming stone

This is what I have so far. Open to ideas suggestions. Really want this deck to be fun yet competitive.

Maybe a No Mercy  to protect you. However the biggest issue i see is flying creatures.

Throw in some spot removal.  Doom Blades, Go for the Throats, Innocent Bloods.  Some Ghost Quarter to deal with Kessig's Wolf Run.

I have a deck based on Relentless Rats that I really have to get around to uploading!!!

Notable cards are Swarm of Rats, Pestilence Rats, Typhoid Rats and the Lord of my deck (and one of my fav cards), Marrow-Gnawer. For other cool rat creatures, check out the Kamigawa block.

When you get a lot of rats with Marrow-Gnawer, an Akroma's Memorial would be so funny xDD, but I think that you have a few possibilities to do this in a seriously match.
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Nighteyes the Desercrator would be good with control cards like Doom Blade or Thoughtseize.
Also, some "finish" spells like Nocturnal Raid can help you to strike a lethal hit. But if ou prefer you can use enchants to increase the power of your rats (Bad Moon for example). And you need something in sideboard vs white control decks with wrath of god and that kind of spells, but mono black I don't know :S

EDIT: The link of Nezumi Graverobber don't works good, search it in the DB by name.
EDIT2: Fixed changing by Nighteyes the Desercrator.

Splash green with doubling chant and overrun

Splash green with doubling chant and overrun

Doubling Chant would be great here, since you could cast it with 6 Relentless Rats on the table and go get another 6.   

 I wouldn't recommend Overrun simply because it's 2GGG and slashing to get three green mana in a Black deck just isn't worth it.  Besides, if you nail your Thrumming Stone you'll have a hoard of enormous rats anyway.

A splash for the chant is worth it anyway

With green in the deck you can include some Strength in Numbers and put it on unblocked rat to strike the final hit (or blocked if u want kill some creature also it gives trample).
And add a Bloodbond March, of course xDD
Mono black full rats you can add a Desperate Research.

I like beastmaster's acension  better

4 acension on the field and u hit with 10 rentless, they'll all be 31/31. Theyll all cost 3. Very funny

eldrazi monument ooks lot of fun

Aether Vial and leave it with 3 charges (this is a free rat each turn).