In a format like Legacy or Modern, where the power levels of all the best decks are comparable, it might be best to pick a deck and learn the ins-and-outs, tuning it to fit your needs. However, in Standard, being able to adapt week-to-week, switching decks when there's a new hole in the metagame, is a very important skill to have. Just ask Brad Nelson.
While plenty of people are relatively successful just copying decks, I've found that understanding the "why"s and "how"s leads to more success in the long term. Not only will you be able to use those skills in order to pick the correct deck for the weekend, but it will be easier to fix the problems your current deck already has.
Clearly, black devotion decks are public enemy number one, but I think we could be doing a better job at fighting them.
Black devotion decks are defined by Thoughtseize and Hero's Downfall, or rather, their ability to deal with problematic permanents that a nearly mono-black deck might have an impossible time dealing with in a different format. Add in the fact that you have Abrupt Decay or Banishing Light as potential splashes alongside plenty of powerful things to do at any point in the curve, and you have a recipe for success.
Basically, black devotion decks are the Jund decks of last year; except they don't rely on drawing Farseek, they have a lower mana curve, and they have a better manabase. They are also far more proactive, with huge threats starting as early as turn two. Typically, fighting a midrange deck with a powerful synergy has been the way to go, but those strategies fall flat against Thoughtseize and sometimes even Pack Rat.
So what's a brewer to do when black devotion decks are playing the role of Fun Police?
Option #1: Go Over the Top
"Going over the top" generally means that you're doing some powerful Stage III thing while they're stuck in Stage II. Elspeth, Sun's Champion; Garruk, Caller of Beasts; and Sphinx's Revelation are currently the primary ways to do that. If they're going over the top against you, you typically feel helpless because you can't break through their soldier tokens or their mountain of card advantage. If you don't have any Stage III plans yourself, your only hope is to kill them before they get to that point.
U/W Control has long used this plan as a means of fighting black devotion decks, but it's not that simple. They have to weather the early discard spells, the threats, and the Underworld Connections; lest they be buried in an avalanche of card advantage themselves.
The best way to do it is by having redundant cards, giving them no good options with Thoughtseize. That can be a little tricky, as having a fist full of Elspeths and Revelations is going to do you no good in Stage I, while they might take your lone Detention Sphere and ride Underworld Connections to victory.
A steady stream of card drawing helps here, but you also need removal in order to not get nickel-and-dimed out by Pack Rat, Lifebane Zombie, Desecration Demon, and eventually, Gray Merchant of Asphodel. Most of the games that U/W Control wins involve them answering threats each turn; maybe drawing some extra cards off Jace, Architect of Thought, and topdecking an Elspeth, Sun's Champion or Sphinx's Revelation at a key point which seals the game.
All of that requires that you draw the right things in the right order, which can be incredibly difficult.
With Temple of Malady now in the mix, black decks have Abrupt Decay to free their Underworld Connections from Detention Sphere. That means that countering Underworld Connections or outright destroying it is far more reliable than Detention Sphere.
The trick to winning with black devotion against U/W Control is winning the games where you've successfully protected your Underworld Connections. Unfortunately, they're going start casting Sphinx's Revelations. You might be able to keep up for a while, but eventually, they'll bury you. A card like Primeval Bounty is great in those situations, as it allows you to keep up with a Sphinx's Revelation or two by turning every Courser of Kruphix and Mutavault into a huge threat they must answer.
Primeval Bounty forces them to spend their turn answering your threats that would have otherwise been relatively meaningless in the face of a Sphinx's Revelation for six. When you can attack them for ten, they might not be able to cast that Sphinx's Revelation, which in turn, might give you a window to nab it with a Thoughtseize or Duress.
Erebos, God of the Dead is another card worth mentioning. It might lose in a heads-up fight against Elspeth, Sun's Champion, but if you have Underworld Connections, (or have drawn a bunch of cards from Erebos) and they're casting Sphinx's Revelation, preventing them from gaining life achieves the same goal as Primeval Bounty. You're forcing them to react to your board instead of getting further ahead on cards.
There are other decks out there that attempt to go over the top, such as various Sphere of Safety / Eidolon of Blossoms "Enchantress" decks and green devotion decks, but nothing has materialized as a significant threat.
Option #2: Go Under
One-drops are scary. They put enough pressure on the black decks that Pack Rat isn't enough to stabilize. Without mass removal, the black deck's Hero's Downfalls aren't going to be able to keep up with your Soldier of the Pantheons or Burning-Tree Emissaries. Drown in Sorrow is almost never seen in maindecks and only occasionally in sideboards, but I like having access to them because people trying to go under me is one of the few ways I can actually be exploited.
Again, Temple of Malady helps the black decks a lot, as they gain access to Golgari Charm. Golgari Charm can function as a Drown in Sorrow against a lot of the decks trying to go under you. Going under might work against black devotion decks in game 1, but if they are prepared, cards like Drown in Sorrow, Golgari Charm, and even Pharika's Cure are going to ruin your day.
Cards like Hall of Triumph help fight off the -X/-X cards, both by putting your creatures out of range, but also by making it less necessary to overextend into their sweepers. However, if you don't overextend, you might just lose to Pack Rat or Desecration Demon. Be careful.
At the end of the day, it's basically up to the black devotion player whether or not they want to defeat decks that attempt to go under them. Sometimes, they don't respect those decks enough and you might be able to capitalize.
Option #3: Exploit a Weakness
Burn is the obvious (non-Blood Baron of Vizkopa) foil to black decks because it renders Thoughtseize and their plethora of removal nearly useless. Desecration Demon and Pack Rat are the cards that matter because Burn might not be able to contain them, which allows black to race. Searing Blood and Chained to the Rocks are a necessity because they check those threats, allowing Burn to continue its game plan.
Gray Merchant of Asphodel is another potential threat to Burn, but one that Skullcrack checks nicely. Additionally, the aforementioned Searing Blood and Chained to the Rocks allow Burn to keep black's board relatively clear of things like Lifebane Zombie that might otherwise fuel bigger Gray Merchant swings.
Nightveil Specter can be an issue for Burn since it's great with Gray Merchant of Asphodel, blocks Chandra's Phoenix, and doesn't die to Searing Blood. Additionally, Lifebane Zombie is much better against the field and that allows Burn to thrive.
When approaching the metagame from a Burn perspective, it's important to note why the deck does well against black devotion decks, and make sure you don't lose sight of that. For example, I see a lot of people cutting Shock in favor of more powerful things, such as Toil//Trouble. I'd recommend against that. Shock is a card that can take care of Pack Rat and Lifebane Zombie, giving Burn more breathing room, and ultimately, more draw steps.
This is very reminiscent of Mono-Red vs. Caw-Blade back in the day, where if the red deck can prevent public enemy number one from getting any traction, they have inevitability. Basically, if you can keep their board relatively clear, eventually red will cobble together a way to deal twenty damage.
From the black side of things, Nightveil Specter does a mountain of good. Despite being a Burn deck, they actually have few things that deal with creatures since most of their burn goes to the face. Nightveil Specter will often eat a Lightning Strike, or it will stay in play for the whole game. If it gets Chained to the Rocks, that might open the door for Desecration Demon to start hitting them hard and potentially give you a buffer with Devour Flesh if necessary.
Anything that gains life, such as Staff of the Death Magus, isn't going to beat the Burn deck on its own because eventually you'll run out of cards. You need to use Staff as a tool that buys you time to get some semblance of a board position and start clocking them.
Hexproof and Dredge also do a pretty good job of fighting black devotion, but they are somewhat inconsistent. Play them at your own risk.
Option #4: Beat Them at Their Own Game
There is no shame in playing the best deck. Several prominent Magicians have attempted to play by their own rules (myself included), but as I always tell them--and should tell myself more often-- you don't get four points for a win when you handicap yourself. If the best choice for a tournament is the best deck, you should probably be playing it.
So you want to play the deck with the target on its head? That's understandable, especially since there isn't a clear hoser out there. Even if there was, you still have Thoughtseize and potentially Duress to fall back on.
But what strategy is best in the mirror match? To figure that out, we need to think about what types of games happen in the mirror.
#2: The game devolves into a topdeck war where someone draws a threat that goes unanswered. Either both or neither player has Underworld Connections.
#3: One player probably has an Underworld Connections active, but is getting nickel-and-dimed by Mutavaults and other assorted threats. That player eventually gets burned out by a Gray Merchant of Asphodel or two. It's one of those games where the player who lost walks away wondering how that could have happened.
I guess we could go by the old Faeries maxim of "There are games where neither player has Bitterblossom, both players have Bitterblossom, or one player has Bitterblossom while the other player doesn't."
In the case of black devotion, it comes down to Pack Rat superiority or Underworld Connections superiority. Born of the Gods changed that with Bile Blight, making it difficult to go all-in on Rats, whereas Journey into Nyx brought Temple of Malady, which made splashing Abrupt Decay appealing.
Unlike the Faeries mirror, we actually have answers to the problematic cards now, but I'm not sure if that makes the matchup any easier to understand.
I think the most important rule is "don't die." You might be able to milk Underworld Connections for a few extra cards, but every time you let that Mutavault or Lifebane Zombie hit you, that makes for less cards you'll draw in the future. It also makes it easier for them to drain you out with Gray Merchant of Asphodel.
After that, the best thing you can do is topdeck better than them, which isn't entirely out of your hands. Several players advocate cutting Desecration Demons in the mirror, which is understandable since it matches up poorly to nearly every available removal spell. However, once you become that threat-light, it's not difficult for your opponent to draw a threat while you're drawing air like Duress.
Decks like Junk are good at accomplishing this. Since they have a plethora of enters-the-battlefield-tapped lands, no two-drop they want to protect like Pack Rat, and answers to anything thanks to Abrupt Decay, Banishing Light, and Hero's Downfall, the necessity for Thoughtseize drops significantly. Instead, they can load up on cards that are good at almost any stage in the game like Advent of the Wurm and Blood Baron of Vizkopa. Because of this, Underworld Connections is less important, as you'd rather be jamming threats every turn rather than trying to outdraw them.
The flipside is twofold. First, your deck becomes pretty clunky with all the lands and color-intensive spells. Much of the time, you'll get beaten down before you get a chance to play your spells. With black devotion decks, the scarce resource is often cards, not mana since the mana curve is typically pretty low. Once you venture into Junk or B/W territory, the scarce resource tends to be mana, which is an important distinction to note. Even though the decks play out relatively the same way, what's important changes.
Secondly, without Thoughtseize and an engine like Underworld Connections, you're going to have a more difficult time against Sphinx's Revelation. You can make up for that with a good sideboard plan, but your game 1 percentage is often very low.
Of the decks mentioned, I think nearly all of them have potential. Burn has clearly been the most successful, but that's mostly because it's not respected, and people don't want to do things like play four Staff of the Death Magus in the sideboard just for one matchup. Junk, Dredge, and Hexproof are all fringe archetypes with minimal success, but it never surprises me to see them do well. Brad's Brave Naya deck is another contender worth checking out.
So now that we have these potential strategies, how do we tune them and fix their bad matchups? Perhaps that's a topic for another day...