Take out two Sire Of Insanity and add two Guttersnipe considering you have a combined 16 instant and sorcery cards.

Building a similar deck myself with stormbreath and demon. Look at rakdos charm for sideboard...mono blue hate when they dump tokens and you burn their face. +1 for the sire!

I would run 4 Pack Rat in the mainboard and take out 2 Sire Of Insanity . With all those lands that you dont need late game you could eat them with Pack Rat 's ability. Also if its a control deck i would sideboard 4 Lifebane Zombie instead of the nightveils. Looks good though. +1 for me.

Also i would take out the guildgates. since you have mostly black in this deck, you shouldnt need that many duel lands.

Temple of malice comin soon...bye bye gates

@zgleason I feel that Pack Rat is only good Mainboard if I'm going exclusively Mono-Black Devotion, otherwise it should stay to Sideboard for when I need an alternative win-con late game. Lifebane Zombie doesn't quite cut it for me in my local meta, as most of the decks here run Black or Red as their base colors, though I suppose I could swap them for Nightveil Specter if I were to go for more serious events. Guildgates are in at the moment to make sure I hit at least 1 Red source early on, so I can Magma Jet if needed. I'm hoping to replace those with the new Scry Lands coming soon :)

@biggod71 I'm trying to fit the Rakdos Charm in somehow, not sure what to swap out for it. I should probably just remove the Anger of the Gods completely, since double red is pretty hard to hit with this deck. As for the Guildgates, that's what I'm thinking xD

Have you considered running Stormbreath Dragon instead of Gray Merchant of Asphodel ? With all the removal in my meta, my Grixis never has enough board presence to drop Gary for more than 3 or 4, and I run a similar creature set. I feel that Stormy could do work in this deck, especially if you come up against Azorius Control, which has exploded onto the scene in my area (5 decks at FNM, all the same).

@Johnny5 I tried running 2x Stormbreath Dragon main over Master of Cruelties .

Honestly, only against U/W/x Control matchups would I play stormbreath. While Stormdrag is a great card, I don't feel it fits into this decklist that well due to lack of synergy. I'm trying to push off any early aggression and last long enough into the mid/late game to finish off with my assorted Demons. Stormdrag is really more of a rush-to-win type card, and his Monstrous doesn't mingle well with Rakdos's Return and Sire Of Insanity .

Thanks for the suggestion though, I just really wish there were something else I could put into the 4/5 drop slot. Liliana's Reaver is a no go, and Erebos is too conditional to be a consistant creature. Maybe Shadowborn Demon ?