ebaskes

I like Nirkana Revenant a lot. That lady is a BEAST. I definitely like her more than Nightmare, that's just me, though.
Although Nightmare Incursion may be a little bit more flavorful, I think that you're better off with Sadistic Sacrament. It's more effective early game and has a huge late game effect. In MB it's rarely going to be a dead drop and can eviscerate most combo decks. HOWEVER, while these cards can be very good against combo, they don't create any effect on the game state, so they're rather matchup dependant. Against aggro or even control they act as -1 on hand advantage which makes them not as useful.
You could maybe run a copy or two of mutilate. It's really quite good. Maybe even SB it if you don't want it MB.
Typically, Victim of Night is going to be better in Modern than Go for the Throat (or hero's downfall) because of affinity, but this is slightly dependant on your play group. Also, your deck is lacking in early game, so maybe you could try running something like Disfigure to take out early threats.
Also, cards like read the bones or sign in blood are never bad choices because hand advantage is everything and paying a small amount of life is negligible, especially when you're running cards like Corrupt and Tendrils, which can gain you big chunks of life back.
Lashwrithe is a beast in monoblack. I run it in my MB aggro deck and never peak over four lands, so in this deck it will pull even more weight. If you drop it on turn four, you can pay four life, stick it on Vampire Nighthawk and swing for 6/7, flying/lifelink/deathtouch and suddenly you have made an eight point life swing and created a monster that most decks will struggle to match and is all but out of reach of direct damage. Most things in modern can't keep up with it (sans emrakul) and if it does manage to get killed, you've still got a powerful equipment sitting on the field.

I love monoblack! This is so simple but effective. Maybe try adding a Demonic Tutor. Innocent blood, ulcerate, disfigure, or contagion are all solid removal options, which you seem to be lacking.
Cool deck!

I think I would be correct in saying that you should only be running one Laboratory maniac. He serves no purpose in your deck until you have combo'd off at which point you will have drawn into him regardless of how many you're running. You want to never see him until you want to.

95% of the time path will be for removal, but now you will know that it's that 5% of the time when it becomes a ramp spell. The heavens will open up as you realize that the "drawback" actually came in handy!
But seriously, it's arguably the best removal spell in the format.

You're right, Gavony Township is definitely a better fit in this deck.

Looks a lot better... You've got a tough looking deck here!!

Sounds good!
+1

-all your off color fetch lands (arid mesa, flooded strand, marsh flats) -1 steam vents for a total of -7
+2 polluted delta, +2 swamp, +2 mountain, +1 island for a total of +7

That should do the trick.... If not, someone will correct me, lol

Very nice looking storm deck.
+1

Looks like a solid UB delver build. +1!

Noxious revival is better than Treasured Find. Sure, it doesn't replace itself, but it can be cast for free and it can disrupt an opponent's top decks late game as well as returning a card that you need. I suggest running a few copies of Life from the Loam as it can act as both an engine and a way for you to get your lands back, which this deck is already a little light on.
I'm not sure of your budget, but cards like Maelstrom Pulse, inquisition of Kozilek, and abrupt decay will do dastardly things for you. Also fetch and shocklands are pretty cool.
I don't think you need four putrefy. Maybe try just one or two and fill the other two (three) spots with cards like dismember, disfigure, or victim of night.
Having at least one Urborg, tomb of Yawgmoth is a given for any deck playing black and another color and it will give you greater access to things like Treetop Village (which can put in some real mileage for you). I don't think you need four crypt of agadeem, maybe just one or two, it seems a little slow.
Personally, I would run Gravecrawler over deadly recluse, or, if money is an issue, Bloodsoaked champion. They both have excellent synergy with Lotleth troll and there's no harm in picking a fatter creature over them to Grisly Salvage.
I like your choice to run Death's shadow, but he can be a dead draw, maybe just two or three and include an extra land or two. Twenty is maybe too few. Try something like 22-24.

Overall, cool deck, but I think some of the tweaks I listed will help out a lot.

A couple things. Firstly, cut out white. It's not doing much aside from mucking with your land base. Take lightning helix out for lightning bolt and you're good on that front. Now you're down to grixis. Nextly, 4 urborg is too many urborg. Go to two or three. Same goes for vendillion clique, probably max that out at 2. Instead, run two Tasigur, the golden fang. He is a huge bomb and kick ass in grixis.
Then I would say -1 flame jab, -1 raven's crime, -1 oona's grace, and -1 dismember and +4 Inquisition of Kozilek.

If you do all these things your deck should run a little smoother and be a lot more potent.

If you're dead set on playing four colors then you need to cut out Phyrexian obliterator. He is just too taxing on your mana base to be in a four color deck, he is even stretching it in three. If this is the case then you should run a playset of lingering souls or and gurmag angler bc he fills the same spot at a lighter colour requirement.

As a MBC player myself, I like this. The inclusion of Flagstones is nice but maybe you have one too many given its legendary status.
I suggest -1 Sorin, -1 Elspeth, +2 Dark Confidant.
Looks like a cool deck though, ill give this a whirl on cockatrice.

I do like aberration. He's a little on the slow side, though and fills a similar spot to phenax but is more susceptible to removal. If I'm spending five cmc I want it to have a lasting, positive effect on the board and aberration is apt to be hit, especially by black/white removal.
Wight is pretty cool but against decks that are light on creatures he becomes more of a dead draw. He will do well in the sideboard though. I will build that now.

Yeah, I know right? It's kinda stupidly expensive. I could never afford something like this, lol. I just think it's fun to make

http://www.mtgvault.com/ebaskes/decks/fathom-a-maniac-in-a-library/

well, here it is. I hope it's okay that I made it, if not, please let me know so that I can take it down.

would it be okay if i made a version of this deck and gave you credit for the idea? I want to build a budget-less version.

additionally, you could add 'Vitu-ghazi, the city tree' for a cheap source of renewable chumpers

sorry, this deck has just gotten me really excited :D

also detention sphere is a lot better than Oblivion Ring

Really cool combo!!!!

I highly recommend adding: Wall of Omens and maybe Courser of Kruphix

Depending on your budget, Fetch-lands, Shock-lands, Remand, and Path to Exile would make this deck infinitely more competitive.

Overall, this is a really cool combo that i've never thought of before. Awesome!