Karumonix, the Rat King is a Legendary Creature from the Phyrexia All Will Be One set for Magic the Gathering. This one is a real doozy, as it’s perhaps the best Rat creature ever printed thus far for EDH and should even be at the core of a Rat deck in Standard, Pioneer, and even Modern. The newest Phyrexia set debuts the Toxic mechanic, which is Infect taken to a new level. This Toxic ability is prominently featured on Karumonix, making it an instantly fascinating card to review.
While Toxic doesn’t deal damage to creatures in the form of -1/-1 counters like Infect, when a creature with Toxic deals combat damage to a player, it deals not only its regular damage, but adds a poison counter to that player, too. Just as it always has been, once a player accumulates 10 poison counters, that player loses the game.
Overall, Toxic is a bit more balanced than Infect because each creature will only deliver one poison counter. With Infect, you could use power-pumping spells to one-shot a player. With Toxic, this is not nearly as simple of a proposition. That said, the Toxic ability and the Rat King still can finish players off with one fell swoop with enough setup.
Karumonix, the Rat King itself is a 3/3 body that with a mana value of three, costing one generic and two Black mana to cast. Not only does he have Toxic 1 himself, but other Rats you control also now have Toxic 1 when he is in play. Plus, when Karumonix enters the Battlefield, you dig five cards deep into your library, reveal any number of Rat cards among them, put them into your hand, then put the other cards at the bottom of your library in a random order.
How Good is Karumonix the Rat King in a Modern Deck?
Rats have long been a niche, but fun Tribal deck in the Modern Constructed format. This is due to the power level of Pack Rat, which can continue to copy themselves at the cost of three mana and the discarding of a card. Other Rats stack hand-control effects, such as Burglar Rat (who forces an opponent to discard a rat), Chittering Rats (which forces an opponent to put a card from their hand back on top of their deck), and Nezumi Shortfang, who can tap and for two mana force an opponent to discard a card.
Shortfang is particularly fun once your opponent has no cards left in hand, transforming into Stabwhisker the Odious. While it doesn’t happen often, when it does, it has a similar effect to the classic card known as The Rack. Like The Rack, each turn your opponent has fewer than three cards in hand, they take damage.
The Rats deck also has Piper of the Swarm, which gives all Rats menace, meaning that it takes two or more creatures just to block one Rat, plus a couple of other good abilities. There’s also the Legendary Marrow-Gnawer who gives Rats fear, meaning they can only be blocked by Black or artifact creatures. But, its tap ability is really why you play this, allowing you to sacrifice a single Rat to put X 1/1 Rat creature tokens into play, where X is the number of Rats you control.
The deck is then rounded out by many copies of Rat Colony, of which you can play any number in a deck. This is typically around the thirteen copy mark. For each other Rat you control, Rat Colony gains one power.
For non-creatures, the deck typically only plays Aether Vial, in order to be able to cheat out cheap rats every single turn. The rest of the deck is the mana base, four of them being Swarmyard which can tap to regenerate a target Rat, and four more being Mutavault, which can animate themselves and also become Rats.
There’s plenty of room for Karumonix to enter the fray here. You could drop the Chittering Rats package entirely in order to keep the mana curve the same. Of course, Phyrexia All Will Be One will give us other options to replace copies of Nezumi Shortfang or even Rat Colony to shore up the overall power level of the deck. But, Karumonix works very well alongside Marrow-Gnawer’s ability to produce a ton of Rats in a hurry at instant speed. It doesn’t take very many Rats to deal ten poison damage, especially if your Burglar Rats and whatever other hand-control Rats which remain are slowing your opponent down to a crawl.
It’s also possible that Karumonix and other Rats from Phyrexia All Will Be One might make this Rat Tribal deck actually competitive. That means you’ll see more typically hand removal such as Thoughtseize or Inquisition of Kozilek instead of Burglar Rat, Nezumi Shortfang, or Chittering Rats entirely. This allows the deck to focus entirely on Pack Rat, Rat Colony, and Piper of the Swarm building the Rat army. You may even see some removal included for a more balanced, competitive feeling deck. I’m curious to see what lists emerge.
How Good is Karumonix the Rat King in EDH?
In EDH, Rats already have a few pretty good choices for their Commander. But, as good as their newest Rat Tribal commander in Ashcoat of the Shadow Swarm can be, none of the existing options measure up to the game-ending potential that is Karumonix. The beauty of this Rat King is that all he has to do is be in play. He doesn’t even have to enter play until you already have enough Rats to poison everyone else out of the game.
That said, Ashcoat is going to be crucial to the Karumonix game-plan, as when he swings, the Warlock powers up your attacking Rats to an absurd degree. Plus, his ability to mill four cards and return two Rats back into play is going to also be extremely helpful.
Marrow-Gnawer is clearly still the best non-Karumonix Legendary Creature, as we’ve already talked about in the Modern version of Rat Tribal. Ink-Eyes, Servant of Oni, Patron of the Nezumi, and Nashi, Moon Scion’s Sage should all feature in a Karumonix EDH deck in a supporting role, as well.
While Greasefang, Okiba Boss decks are better equipped for swarming Vehicles, there exist Rat Colony builds of the deck. These builds are more than likely to acquire a copy of Karumonix, the Rat King for an alternative win condition.
There’s already the shell of a Karumonix, the Rat King EDH deck (with Sheoldred, the Apocalypse listed as the Commander) already on MTG Goldfish centered around Relentless Rats. I’m excited to see how these decks evolve as we get more support for the Rat tribe in Phyrexia All Will Be One and further releases.
How good is the Toxic ability compared to Infect?
While Toxic is certainly a powered-down version of Infect, because Rats can swarm so efficiently, it doesn’t take much to see Toxic Rats as a legitimate win condition. I am happy that you can’t simply use pump spells, and that Ashcoat can’t come out of the woodwork to boost this deck further, as he’s not Modern or Pioneer legal. In any case, you will need ten separate attacks to take out a player, so it’s at least balanced.
I’m also curious to see just how much the Toxic ability is seen outside of Rat Tribal, or if this is going to be a thing just for Rats to be more competitive in both the short and long term. There are Phyrexian Mite creatures with Toxic in the Phyrexia All Will Be One set, for example. It will be interesting to see the interplay between Mites and Rats in the upcoming Standard.
Karumonix, the Rat King is the missing piece that Rat Tribal needed to be a serious threat in Modern. I’m excited to see what Standard brews emerge, and to see just how much scarier Rats will become as a Tribe in EDH and perhaps even Pioneer.