A couple of years ago, Infect barely saw any play whatsoever. Now Infect is known as one of the most powerful decks in Modern, and a contender in Legacy. So what changed?
Players like Tom Ross certainly played a role in promoting the deck, but finding the right mix of infect creatures and pump spells isn't easy. Early versions of Infect tried to play more infect creatures instead of the current versions that protect the few creatures the deck actually wants to play.
In Modern, B/G Infect does see a little bit of play, but is much less popular when compared to its U/G counterpart. Playing an aggressive deck with blue in it has a lot of added benefits in Modern, and even more so in Legacy. One of the best infect creatures happens to be Blighted Agent.
In both Legacy and Modern, the Infect deck revolves around the same 12 Infect threats: Glistener Elf, Blighted Agent, and Inkmoth Nexus, alongside Noble Hierarch, are the tried and proven core creatures.
The manabase is pretty straightforward, but actually plays two copies of Pendelhaven. Pendelhaven is legendary, which means running two copies is a liability, but the power behind this card is so significant that playing two is worth it.
There are a variety of ways to pump infect creatures. One of the pump effects, which is absent from this list, is Groundswell. Groundswell is in many ways similar to Might of Old Krosa, but by not playing it there isn't a need to constantly have a land available to play or a fetchland already in play.
There can only be so many pump effects, as there also need to be ways to protect your creatures. Since the deck plays so few creatures, oftentimes it is necessary to leave mana up in order to represent a way to counter opposing one-for-one removal spells. This list plays Vines of Vastwood and Apostle's Blessing as protection spells. These cards can protect your creatures, but Vines of Wastwood pulls double-duty as a pump spell, and Apostle's Blessing can make a creature unblockable. Sometimes a Blighted Agent is unavailable so having a way to get through opposing blockers, including those that have flying, is important. Infect has a good Affinity matchup and Apostle's Blessing is a big reason why.
As far as the big pump spells, Become Immense is the one that stands out the most, in many ways. There are definitely a few different ways to make your creatures bigger in this deck, but Become Immense provides the biggest boost. This deck plays a full four copies of Become Immense, which is a lot for a card with delve. Drawing two Become Immense can backfire depending on how easy it is to fill up the graveyard. The deck does play cards that are good at making sure the graveyard is fully stocked in order to justify this many copies of Become Immense.
This list does play one other Infect creature and that is the singleton Viridian Corrupter. Viridian Corrupter is maindeckable, but gets boarded out against every deck that doesn't play artifacts. As a three mana creature that is just an infect threat it isn't particularly impressive, but when you do actually destroy something with this guy it is a pretty big blowout. One of the most commonly played cards in order to combat Infect is Spellskite, so having another answer to it that doubles as an infect threat is nice. In both Legacy and Modern Viridian Corrupter can crop up as a singleton pretty frequently. Twisted Image is another card we see in the maindeck, and in many ways the card is at its best in the mirror! Taking out Spellskite is the best-case scenario, but also just using a Twisted Image on a Noble Hierach or Birds of Paradise is a big deal.
The sideboard of the Modern Infect deck seems to be constantly changing. It is pretty well-known that Infect has trouble dealing with Burn and other aggressive strategies, which is why we now see four Kitchen Finks in the board. For quite a while Infect went without having any type of lifegain in the board, but currently most lists do have Kitchen Finks, despite this not helping kill the opponent, it can buy you crucial time.
While Modern Infect is already an established powerhouse, Legacy Infect isn't quite as well known, though the deck has been consistently putting up results for a little while now. This past weekend Infect actually took down Grand Prix Columbus, one of the few Legacy GPs this year. I also played Infect in Columbus. Now that I have experience with Infect in multiple formats, it is safe to say that while the goal of dealing the opponent ten damage is simple, the execution can be difficult.
We see that there is a fair amount of overlap with Modern, but there are also some Legacy staples in the deck that aren't legal in Modern. When comparing this list to its Modern counterpart we see that there isn't as much of a need to play so many pump spells in the Legacy list. In Legacy you really want to be able to play a single Infect creature, and then be able to kill the opponent by using only two pump effects. The best possible pump effect is Invigorate, which is essentially zero mana for a four-power boost, which is crazy. The funny thing is Invigorate never really saw much play until players suddenly started trying to play Legacy Infect, and now it is having its time to shine.
The best card to couple with Invigorate is Berserk. Alongside Invigorate, it creates a ten-power creature, off an investment of G. Invigorate can also help create, in rare situations, a kill with direct damage from Noble Hierarch. Doubling a creature's power and then tacking on trample, can make creatures insanely big, when combined with other pump effects. The part about Berserk most players don't realize, however, is the ability to use it on an opposing creature as a form of removal. You are only going to cast a Berserk on your creature when it represents lethal damage, so the creature dying at the end of combat doesn't actually come up all that often.
Unlike the Modern version where the blue cards offer a bit of support but green is the star of the show, in the Legacy version blue is actually the more prevalent color. This deck is playing Force of Will, a classic Legacy staple, and that card of course requires running a host of other blue cards alongside it. Rather than playing a lot of actual protection spells this deck leans on countermagic more to stop opposing removal when moving in for the kill. Alongside Force of Will there is also a playset of Daze which are pretty tough for an opponent to play around. This deck doesn't need many lands at all in order to function, so returning an Island to use a Daze isn't much of a drawback.
Playing four Brainstorm is obvious, but it is worth noting that the more cantrip type cards the deck plays, the more you can trim on other cards in the deck. For instance there is only one Become Immense here, whereas the Modern version plays four. With cards like Brainstorm, finding that singleton Become Immense is much easier than it is in Modern. There is also a singleton Sylvan Library as a great card to have against Miracles, and a useful tool in any sort of prolonged game. Both Become Immense and Sylvan Library are powerful cards that are not impressive in multiples.
The issue with relying on Inkmoth Nexus to win the game is that there are a lot of Wastelands lurking around Legacy. Inkmoth Nexus is in many ways actually the most important Infect creature, and here there are actually more ways to go and find Inkmoth Nexus. Crop Rotation is here to find Inkmoth Nexus, and, in the best-case scenario, can be used in response to an opposing Wasteland so that the land targeted by Wasteland gets sacrificed to Crop Rotation. Most Infect lists only play one Crop Rotation maindeck, but here we see two alongside a couple of silver bullet lands which can also be searched for. Crop Rotation for your own Wasteland or the Bojuka Bog out of the board can be pretty sweet.
One card which hasn't been mentioned yet but is in both the Modern and Legacy Infect deck is Gitaxian Probe. Knowing the opponents hand when playing Infect really does have a ton of value, as it lets you know if the coast is clear to go for the kill, by firing off pump spells. In the Legacy version it is also just another blue card which can be pitched to Force of Will if necessary. A card like Gitaxian Probe can go under the radar but this deck wants to be going for a kill on turn two or three, and this fills up the graveyard for delve, costs actual zero mana, and provides critical information on how the game will play out.
At this point it is safe to say that both the Legacy and Modern versions of Infect are good decks. In many ways, an Infect deck completely changes a format, as it makes having interaction for opposing creatures much more important. The slightly slower combo decks have been struggling a bit due to the presence of decks like Infect which can win quickly, and have built-in disruption and countermagic.
Thanks for reading,