You get both the best one-drop and burn spell in standard with the caveat being you have to build your deck to draw a ton of cards. Boros Cycling is an aggressive deck capable of attacking from a variety of angles, giving it the ability to play around a large number of cards. With Drannith Healer and Zenith Flare the deck is also able to gain a fair amount of life while enacting it’s gameplan, giving it a built in anti-aggro measure.
The deck’s worst matchup of Keruga Fires is gone while it’s other poor matchups of Jund and Rakdos Sacrifice may not fair well in the new metagame if Bant Yorion and Temur Reclamation are the top decks (both of which are preferred matchups for cycling).Granted if the sacrifice decks do get bullied out of the format and everyone swaps their Grafdigger’s Cages for Soul-Guide Lanterns then things look a little worse for our hero.
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Alongside Flourishing Fox you have two more creatures used as your main source of pressure: Valiant Rescuer and Drannith Stinger. A good rule of thumb is to mulligan any hand that does not have one of the three. It’s rarer to cast a creature after turn 3, unless it’s post board wipe, at which point you’re just cycling them. The main exception is you will sometimes cast a Stinger on a later turn to help bring them in range of a single Zenith Flare.
While the rule change effectively doubled the cost to play the companion, Lurrus is still a fairly free inclusion for cycling. Without making any drastic changes to the mainboard the only thing you lose by including the nightmare kitty is Imposing Vantasaur as an on color cycler, which if you really want to pay 6 mana for a creature just add Lurrus to your hand and cast it in the same turn. While not in my current list, one card I’ve been testing for the board is Bonecrusher Giant. While Lurrus is still solid against the controlling decks she’s unlikely to be impactful in most aggressive matchups so bringing it a card that removes her as a companion is a low cost. The adventure creature is strong but I’ve found Deafening Clarion to be significantly more impactful in those matchups.
While a board wipe that kills most of your creatures may not seem like something an aggro deck wants it allows you to play a game closer to a midrange deck against aggressive opponents. Either through casting both modes when you have a bigger Flourishing Fox or just by buying time to get to a large Zenith Flare to put yourself out of reach.
You’ll notice I take a land out on the draw, if you have never used a geometric calculator to figure out how likely you are to draw certain cards I highly recommend it. This is looking at lands drawn by turn 3. I added ‘1’ to the number of cards seen as it's a safe assumption that we’ll cycle at least one card on the first two turns.
This is on the play with 18 lands (10 cards seen):
On the draw with 17 lands (11 cards seen):
So even with removing a land our chance of hitting our third land on turn 3 actually goes up from 63.5% to 66.4%. This calculation isn’t perfect as it doesn’t take into account mulligans but you get the idea. You can find the calculator I used at: http://www.kelvinliu.org/mtg_calculator.html
What to cut is fairly straightforward as you’re pretty much always thinning your deck of cyclers you can’t cast, for simplicity I just refer to them below as ‘cyclers’. The exception to this is I will sometimes shave a Zenith Flare if I expect my opponent to have multiple Soul-Guide Lanterns.
+2 Fry -2 Cyclers (-1 cycler, -1 Plains on draw).
You’re reasonably favored game one as they have a slower gameplan you’re able to get under and they have cards like Elspeth Conquers Death that do little against us. Fry is primarily for Narset, Parter of Veils who is fairly strong in the matchup but unlike Jeskai Lukka of standards past they don’t play an abundance of token makers so you can usually answer her through combat. I’m not a fan of Fight as One in this matchup as both Teferi and Glass Casket stop the card from being able to protect your creatures. I don’t like siding too heavily as your main advantage in the matchup comes from your speed, don’t try beating their late game if you don’t have to.
+2 Fight as One +1 Light of Hope -3 cyclers (-2 cyclers, -1 Plains on draw)
Flourishing Fox shines even more in this matchup as it can get out of reach of their burn spells fairly quickly.They still have Blast Zone and Brazzen Borrower for answers but I expect them to play less copies of Borrower now that they don’t have to worry about Lukka. I tend to mulligan more aggressively here as applying pressure early makes it harder for them to keep counter magic up for our Flares.
You want to use Devout Decree or Dragonfire on Annax if possible, but staying alive to cast a giant Zenith Flare and gaining a bunch of life is what usually matters most so use your best judgement. Don’t be afraid to use Flare as a removal spell, your late game is better than theirs so staying alive with a healthy life total is (usually) a path to victory. In this matchup replace Stinger with healer on your 3 important creatures. If you have seen or expect Experimental Frenzy then Light of Hope can come in.
I find this to be the deck’s worst matchup. Between their removal (I include Claim the Firstborn in this) and Cauldron Familiar plus Witch’s Oven it can be harder to get damage in with your foxes. Keep an eye open for when you can use Footfall Crater to allow Flourishing Fox to get through. I usually cut 1 Zenith Flare due to them commonly playing 2-3 Soul-Guide Lanterns.
I’m not sure who was favored in the matchup with the Lurrus versions of Rakdos but if they have Mayhem devil they are. If you’re playing against a more aggressive build with Robber of the Rich I would add the Deafening Clarions, not add Apostle and cut another cycler. This is another matchup I find myself casting Dranith Healer a lot.
The mirror can get a little weird. While one player can run away with the game early it’s rare. Most games go longer, partly because of the huge life swings caused by Zenith Flare, and in these the first player to run out of gas loses (why we cut an extra land). Don’t be afraid to use Zenith Flare as a removal spell, while in a lot of matchups you can ignore the board and play towards burning them out if you do that here you can get blown out by them using their own Zenith Flare to gain a bunch of life in response and kill you with a superior board. Try to keep Foxes under control, you can chump them with tokens from Rescuers but if you rely on that you can get in trouble if they play a Footfall Crater. If you can, try to sandbag your Lurrus until they’re out of removal as the nightmare kitty provides a huge advantage in a grind. Recurring Soul-Guide Lantern with Lurrus each turn is a good way to pull ahead but be cautious sacrificing lantern into open mana as having Lurrus killed in response is a good way to let your opponent back in. If Cycling becomes more popular consider adding additional Soul-Guide Lanterns.