No Master of the Feast or Reliquary Tower?

@Quicksilver Sorry I'm only now getting to your comment. I feel like Master of the Feast is only okay and doesn't do quite enough. I feel like he's unplayable if I don't have one of my draw pains out there as I would only be giving my opponents more cards for their combos with little in return. This is definitely a group game build, not 1v1. I just don't have a copy of Reliquary Tower but it will probably be in my next order.

You could also go with Niv-Mizzet, the Firemind and Curiosity. I would avoid any land that comes into play tapped without the option to untap it. Shock lands and the Innistrad dual lands are good. Urborg, Tomb of Yawgmoth is good for mana fixing. Works well with Crypt Ghast. I would switch Opal Palace for Nykthos, Shrine to Nyx. I'd replace Rupture Spire. It is terrible. I'd put a basic land if nothing else. Unless you can combo out with it, I'd get rid out anything that costs more then five. Go for a cheaper counterpart. Instead of Annihilate go with Go for the Throat. Toss in some signets, Fellwar Stone and a Everflowing Chalice for mana rocks. Cyclonic Rift for Devastation Tide. Hive Mind+ most of the cards in group C. Rhystic Study for card draw. Sensei's Divining Top to help with top decking. Seizan, Perverter of Truth works with group A. And Steel Hellkite to blow stuff up.

@GildarLordOfTheUndead Thanks for the comment!

Here's where we agree: Curiosity - Thanks for the reminder. I have a copy and it will be going in immediately. Urborg, Tomb of Yawgmoth, Nykthos, Shrine to Nyx, dual/shock lands, Sensei's Divining Top - At this point I'm trying to keep this fairly budget and that means cutting corners on lands though I agree these would all be good additions. Go for the Throat - Couldn't agree more. I think I'll make that change and also put in a Dreadbore for Burn Away. Fellwar Stone & Hive Mind - In my next order.

Here's where we might disagree (unless you can change my mind): Cyclonic Rift - Yes, it's instant speed but to board bounce it costs 1 more than Devastation Tide and that's if I don't miracle DT. Everflowing Chalice - I have a copy but not sure it's fast enough. I feel like I would have to basically skip a whole turn 6 or something to get value out of it. Perhaps I just don't see it. Rhystic Study - I have a copy of this as well but never have a problem with card draw. Steel Hellkite - I have a copy of this too but think it is more suited to a 1v1 build and this is a group build. Paying 6 to cast on one turn and then paying X on another turn to wipe only one opponents board seems slow to me. Seizan, Perverter of Truth - I'm in between on this one kind of like Urza's Guilt that I have on my sideboard. Maybe I'll pick up a copy and playtest it a bit.

On second thought, the guys I play with don't have any pact cards so until I get burned by one with Hive Mind, I think I'll keep Fellwar Stone out.

Cyclonic Rift keeps all your group A & B stuff in play. So if you can Cyclonic Rift and use anything from group C they will be taking tons of damage. I did like 72 damage this way in a one on one game in a turn. I'd still switch Obelisk of Grixis for a Fellwar Stone Its cheaper to cast and unless all your opponents are playing all green and white or green/white you will get some use out of it. Really useful when they play a Command Tower. I only cast Hive Mind if i have Nekusar, the Mindrazer out and a 'wheel' in my hand.Try it you might like it.

Yea fellwar stone does nothing for off-color pacts and Hive Mind (mana not in your commanders color becomes colorless if you tap a land for that type). I agree with rocks being really powerful to speed the deck up, Personally I think your biggest gap is some tutor packages, with B you really need diabolic and vampiric at least to tutor up your game enders, they are how you turn a 100 card singleton deck into a 98 card deck with "extra copies" of your important cards.

Black
Diabolic Tutor
Vampiric Tutor
Demonic Tutor

Blue
Merchant Scroll
Mystical Tutor
Personal Tutor
Muddle the Mixture

Also getting some of the Khans fetches for manabase is always nice, good for shuffle effects if you abuse top deck effects more.

@GildarLordOfTheUndead - DOH! I forgot that Cyclonic Rift only removes opponents' permanents not yours. Definitely changing. As for the Fellwar Stone, I'm still not sold but since it is cheap, I'll pick one up and playtest it.

@mumrahte - Tutors/fetch lands are always nice but tutors/fetch lands = $ and I want to keep this pretty budget (I realize I have a Wheel of Fortune but I was able to grab it ridiculously cheap). Merchant Scroll (blue instant) and Muddle the Mixture (2 mana spell) won't bring me much except counters. Diabolic Tutor would be the one I would consider throwing in the deck.

Dark Deal

@klone13 Sweet! I haven't had a chance to check out the new cards but that looks like it will be an auto-include in all Nekusar decks. I'll put it in my maybeboard until I'm able to order it.