So, first of all, I like the approach and I believe you will eventually be able to compete with this deck.

Some thoughts:

I agree with everything wallisface says here. All points are valid.

Second, here's what I'd suggest to adress the concerns:

This is a monocolored deck and you don't need the fetchlands! All they do is cost life and 'thin' your deck, but we realized you need more lands. So, swapping them for Ghost Quarters, Bojuka Bogs, other utility lands, or even basic Swamps would strictly improve your deck imho.

Then, 4 thoughtseize is too much imho, you should go with a 3/3 or 2/4 split Seize/Inq, which doesn't seem like a big deal, but you're gonna hate when those Thoughtseize topdecks become blanks late game because you can't afford the life.

I'd personally swap the Sign in Bloods for removal.

Cheers!

I disagree that IoK should be played over TS in the current meta that is rife with pitch elementals, Murktides, Primeval Titans, and Omnaths. However a 3/3 split could be ok if you find yourself short on life in most games. In place of the Sign in Bloods, I've seen people run a cantrip creature like Dusk Legion Zealot that can block a Ragavan while adding to your devotion count (although I do recognize that the secret mode of sign in blood that can burn your opponent in a pinch can be useful). I'd also cut the Cry of the Carnarium from the MD, adding the 22nd land. Running a few fetches to enable Fatal Push is fine, although I'm not sure you need more than 4 for just that reason. Also, have you run into any issues running Nighthawk Scavenger and Dauthi Voidwalkers together? The Scavenger wouldn't get very big if you played a Voidwalker the turn before. If you need to cut a 3-drop creature, that's where I'd start if you don't want to move the Voidwalkers to the SB.

The bigger issue with your deck is the SB though. With 4 MD Voidwalkers and a Tymaret, you definitely don't need as much grave hate as you currently have. I'd add at least 2 more removal spells that can hit larger creatures to the SB for the matchups that need them. Something that can hit Murktide Regent, Omnath, Locus of Creation, Fury, and Solitude, and that only costs 2 mana. I don't know if you play against much burn or control, but Collective Brutality is a good card against burn, low-to-the-ground aggro, and control decks. Tourach, Dread Cantor is also good right now against white decks like humans, UW control, decks playing Solitude, and in other grindy matchups where the discard is relevant. It also helps get more cards to steal if you have a Voidwalker in play. It doesn't add much to devotion, but it's still a good card in the meta that might work as a 2-of in your SB. Void Mirror is good if you play against Cascade, Tron, and the pitch elementals, and Plague Engineers would be good if you play against Humans, Merfolk, or any other tribal deck. Unearth would be good to bring in against removal-heavy decks, and allows you to aggressively use an early Gifted Aetherborn or Scavenger as a removal spell if needed.

*Also you may want to update in your description, as Sinkhole is not modern legal. It would be awesome if it was since Tron and Amulet can be tough matchups.

I'm very appreciative of everyone's comments and the time taken to write them - you've given me a good bit to think about. I do want to address a few of them, not as an argument but to show where my thinking is/was, if only so you guys can point out to me where I'm mistaken.

wallisface

• It seems to be a consistent belief that Surgical Extraction is being used as some sort of graveyard hate when the point of using it (often in conjunction with Thoughtseize or Inquisition of Kozilek to break combo decks, something you have suggested I would have trouble against. My (current) defense against a lot of the issues you mention is selective hand destruction and then Extracting them out of the deck.

• The thought behind Bad Moon isn't to race Burn so much as it is to nudge most of my creatures past the key 3 Toughness that makes them vulnerable to things like Lightning Bolt or Anger of the Gods.

• I thought Cry of the Carnarium would be of use against a number of weenie decks, from humans to elves, but it is ultimately speculative. Just looking for some sort of mass removal.

• Are you suggesting splashing red solely for side-boarding Blood Moon?

sergiodelrio

• The fetch lands are more for maximizing the effectiveness of Fatal Push than for thinning my deck, which is just a nice side effect. At the moment their benefit is more theoretical as I haven't spent the money to invest in them yet.

• Thoughtseize seemed like the more effective card, and with 11 Lifelink cards (not counting Gray Merchant of Asphodel), I haven't generally run into life problems as a result of it or Sign in Blood.

• With the hand destruction, 4x Fatal Push and 3x Murderous Rider do you really think I still need more removal?

GeminiSpartanX

• I think looking at cantrips (over Sign in Blood) is an interesting idea. It's also interesting that you bring up the seemingly incongruent natures of Nighthawk Scavenger and Dauthi Voidwalker. It seems like I usually end up getting them them in groups of one or the other, but of course that's just randomness. I'm loathe to give up either because the Voidwalker is such a strong and useful card while the Nighthawk is often my best offensive weapon. It is something that bears watching, though.

• I really don't consider Surgical Extraction graveyard hate, but rather a combo deck breaker, especially when used in conjunction with Discard.

• A number of good sideboard suggestions there, exactly what I was hoping for. I actually like the idea of Unearth as a potential replacement for Sign in Blood.

GeminiSpartanX, sergiodelrio, wallisface

Alright, based on some of your suggestions, I've made the following changes to the deck:

Removed:

• 1x Cry of the Carnarium
• 3x Sign in Blood
• 1x Thoughtseize
• 1x Nighthawk Scavenger
• 2x fetch lands

Added:

• 3x Ghost Quarter
• 1x Inquisition of Kozilek
• 1x Tourach, Dread Cantor
• 2x Unearth

This brings my deck size down to 60 and my land count up to 22. With so much black mana required I am a touch skittish about having the additional colorless mana cards in there but I feel like the land destruction really is important.

In my sideboard I also made a few minor changes. I've still got what I need to go full compliment with Discard + Surgical Extraction (it is just a devastating 1-2 punch against pretty much any combo deck), but I tossed in a fourth Murderous Rider for when it seems like I need more removal. For the last two slots I'm currently bouncing back and forth between a pair of Void Mirror or Collective Brutality.

It'll be interesting to test this out.

My only other consideration right now is whether there is a better beat down option out there than Nighthawk Scavenger for the same cost? I admit, I don't love the dis-synergy they have with Dauthi Voidwalker but the scavenger has been so incredibly effective for me in the past, it's tough to let go. I don't want to only rely on Gary and the Obliterator as win-cons, so I definitely want a threat in those slots.

Additional thoughts, if you're still inclined to offer them? If not, then again, I appreciate the ideas already offered.

Are you trying to play competitively, or is this just for fun?

Grubbernaut

Competitively. The deck has done very well when played casually.

StoryArcher just to respond to the 4 bullet-points assigned to me, in order:

• Yes your approach for Surgical Extraction hitting combo is a good one. However, the card also doubles as grave hate, and between having 4 of them, and a mainboard playset of Voidwalker, i think any more is excessive. So I guess i’d suggest to ditch the relics.

• Bad Moon as an answer to bolt seems pretty futile. It could help versus Anger (and Fury), but i think there’s probably more pressing things to be playing in your sideboard. I’ve seen no other competitive devotion decks run Anger-hate, but ultimately it’s a meta call. I suspect Anger is played very seldom now that Fury exists - and Bad Moon isn’t as effective a choice versus that.

• Whether or not to run Cry is again a meta call. I would say if your aim with it is to stomp on weenie-tribal decks, Plague Engineer is a stronger choice, as it will perform a stronger role, while also providing devotion. Cry is a much more situational option.

• Yeah i’m absolutely suggesting splashing red for Blood Moon. It would mean running a single Blood Crypt and 4x Marsh Flats mainboard (i say Marsh Flats over the BR fetch, as this helps disguise your sideboard plan). The amount of games you’ll win against tough-matchups by dropping a cheeky Blood Moon will surprise you. However, the whole package isn’t cheap (shocks/fetches), so unless you already have most the needed cards, i’d suggest seeing how greedy your metas manabase is before committing to it.

For what it’s worth, if i were running this deck, my sideboard’d look something like this:

• 2x Collective Brutality

• 3x Blood Moon

• 1x Inquisition of Kozilek

• 1x Kalitas, Traitor of Ghet

• 2x Plague Engineer

• 2x Void Mirror

• 3x Surgical Extraction

• 1x Thoughtseize

To be frank, I don't think mono B has a realistic chance of competing in the modern meta; it's just too fast, too adaptive. The only route I could see that has a shot is a Lurrus build, IMO.

Fatal Push is also really bad with the elementals and Murktide running rampant, which makes the removal of black really struggle overall; you'll often be either compromising your ability to hit big threats, or using 2-cmc spells to trade down on Ragavan and Esper Sentinel, etc.

With so much cheap removal, too, there will be a lot of times your Gary gets removed before the trigger resolves. And with only 2 Castle and an Erebos to draw cards, it's going to get buried by things like Expressive Iteration, Ragavan flips, etc.

A Lurrus build could let you include Bob, which would give some card advantage.

Dash Hopes is a cheap counterspell that can help set up a victory by forcing the opponent to pay 5 life.

berryjon I would suggest against Dash Hopes. It isn't really a "counterspell", as the opponent will get to decide whether their spell resolves or not - and usually they'll just take the 5 life and think nothing of it. But in either case, the opponent will pick the option that's best for them (and so, worst for you).

Black Devotion wins through board presence and midrange-grind. Its not a deck that gains anything particularly from "burning" the opponent (or they'd be commonly seen running Lightning Bolt). Dash Hopes has no reasonable place here (imo, it doesn't really work in any deck unless you're actively playing something ultra-casual).