Corrupting Influence precon upgrade guide

Culling Ritual destroys every nonland permanent with mana value 2 or less, and 17 of the permanents in this box are exactly that.

Eleven of those 17 are creatures, and 15 of the 22 creatures in the 99 can put a poison counter on a player in combat. The ritual would kill the plan it sits in. It's the loudest of ten cards I'd swap out. The other nine are tax effects in a deck that has to attack, equipment that costs a creature to move, two tapped lands, and a few cards that a better one already covers.

Ixhel, Scion of Atraxa is a 2/5 flier with vigilance and toxic 2, and her Corrupted ability only works once an opponent has three poison counters. At your end step each such opponent exiles the top card of their library face down, and you may play it using mana of any color. Ten counters ends the game. Seven creatures in the box have infect (Blight Mamba, Ichor Rats, Ichorclaw Myr, Phyrexian Swarmlord, Plague Myr, Plague Stinger, Viridian Corrupter) and eight have toxic (Bilious Skulldweller, Blightbelly Rat, Myr Convert, Pestilent Syphoner, Venomous Brutalizer, Contaminant Grafter, Glissa's Retriever, Vishgraz, the Doomhive). Six of them are 1/1s. A toxic creature gives a fixed number of counters per hit whatever its power (one on most, three on Venomous Brutalizer and Glissa's Retriever), and every one of them poisons a single opponent at a time.

That last part decides the upgrades. Each creature poisons only the player it hits, so against three opponents it takes three connections to put all of them on the board. Proliferate does it once. The numbers below come from resolving the shipped decklist and then the upgraded one.

What are the best Corrupting Influence upgrades?

The proliferate engines first, then the finishers, then the mana. Prices are October 2026 market prices at the cheapest released printing, which can be a promo or a Mystical Archive card. The ten adds total $50.64.

1. Bloated Contaminator ($3.35). A 4/4 trampler for {2}{G} with toxic 1 that proliferates every time it deals combat damage to a player. One connection poisons the player it hit, then adds another counter to every poisoned opponent, the one it hit included.
2. Fynn, the Fangbearer ($0.18) and Metastatic Evangel ($0.35). Fynn turns the box's lone deathtouch creature into a three-counter hit. The Evangel proliferates whenever another nontoken creature you control enters. Together they cost 53 cents.
3. Skithiryx, the Blight Dragon ($12.25). A 4/4 flier with infect that can gain haste for {B} and regenerate for {B}{B}. One hit in the air is four counters, past Ixhel's threshold in a single swing.
4. Triumph of the Hordes ($11.31). The finisher, argued below. It ends one opponent, and I'd buy it after the three cards above.
5. Vraska, Betrayal's Sting ($2.79), Drown in Ichor ($0.98) and Skrelv, Defector Mite ($2.87). A planeswalker that proliferates each turn, a removal spell that proliferates, and a one-drop that hands another creature toxic and evasion against one color.
6. Overgrown Tomb ($8.12) and Godless Shrine ($8.44). Two untapped duals, argued in the mana section. Both get a Star Trek reprint on 13 November 2026, and they're the part to buy last.

One creature poisons one opponent. Proliferate reaches all of them.

Twelve cards in the box proliferate: Blightbelly Rat when it dies, Cankerbloom when sacrificed, Contaminant Grafter, Evolution Sage, Grateful Apparition, Norn's Choirmaster, Unnatural Restoration, Vat Emergence, Contagion Clasp, Glistening Sphere and Karn's Bastion, plus Venomous Brutalizer if you pay {1}{G} when it enters. (Expand the Sphere proliferates only if it finds fewer than two lands, so I don't count it.) Most of those fire once. The ones that repeat are Evolution Sage on each land, Grateful Apparition on each hit, Contaminant Grafter on any combat damage, the Choirmaster on each commander attack, and the two {4} activations on the Clasp and the Bastion.

Proliferate adds one counter to each player and permanent you choose that already has one. When all three opponents are at three, one proliferate adds three poison counters across the table and a toxic 1 hit adds one. That asymmetry is why the adds are mostly triggers. Bloated Contaminator fires on every one of its own connections. Metastatic Evangel fires on each other nontoken creature that enters, which is the other 24 creature cards in the 99 plus Ixhel, and none of the Mite or Insect tokens the deck makes. Vraska, Betrayal's Sting enters with 6 loyalty and her 0 ability draws a card, costs you 1 life and proliferates, once a turn. She is one of the permanents you can choose, so she gains a loyalty counter each time and reaches the 9 her last ability needs in three activations. That ability brings a player up to nine counters, not ten, so it sets up a kill and doesn't make one.

Drown in Ichor is the cheap one. It gives a creature -4/-4 for {1}{B} and then proliferates, so it is removal that also adds the counter. After the swaps the list has 16 proliferating cards against 12, not counting Expand the Sphere.

One deathtouch creature in the box, and the card that makes it count

Fynn, the Fangbearer is a 1/3 deathtouch for {1}{G}. Whenever a creature you control with deathtouch deals combat damage to a player, that player gets two poison counters. The box's only deathtouch creature is Bilious Skulldweller, a 1/1 for {B} that already has toxic 1, so with Fynn out it hits for three counters. That's Ixhel's whole threshold in one connection from a one-drop. Fynn has deathtouch herself, which makes her a two-counter attacker as well.

She is a Human Warrior in a deck that is 83% Phyrexian, so a deckbuilder looking for off-type cards would cut her first. It costs nothing here: no card in the box makes you choose a creature type, so the Phyrexian count describes the deck and doesn't power anything. After the swaps the deck is 88% Phyrexian (23 of 26 creatures).

Triumph of the Hordes ends one opponent, and says so

Triumph of the Hordes costs {2}{G}{G}. Until end of turn your creatures get +1/+1 and gain trample and infect, and the ruling is that multiple instances of infect are redundant, so the creatures that already have it lose nothing. Every creature that connects deals its damage as poison counters. A 4/4 such as Bloated Contaminator or Venomous Brutalizer becomes a 5/5 that puts at least five counters on whoever takes it, so two of them connecting is at least ten and a lost game. Blockers soak some of it, and trample carries the rest through. It only affects the creatures you control when it resolves, so cast it in your first main phase with the attackers already out.

That kills one opponent. In a pod of four it leaves two others, so it is a card for the turn the table is already at three or four counters and one player is the problem, not a way to win from nothing. At $11.31 it's the second most expensive add. If the budget is tight, it is the one I'd hold back after the three cheaper engines.

What leaves, starting with the ritual

Culling Ritual destroys each nonland permanent with mana value 2 or less and adds {B} or {G} for each one it destroys. In the box that is 17 of your own permanents: Bilious Skulldweller, Blight Mamba, Blightbelly Rat, Cankerbloom, Grateful Apparition, Ichorclaw Myr, Myr Convert, Pestilent Syphoner, Plague Myr, Plague Stinger and Scavenging Ooze (11 creatures), and Arcane Signet, Contagion Clasp, Fellwar Stone, Golgari Signet, Sol Ring and Trailblazer's Boots (6 artifacts). Every Mite and Insect token the deck makes has mana value 0 and would go with them. The mana is real and then it's gone at end of phase. It stays only if you build the deck around rebuilding afterwards, and this one is built around the small things the ritual kills.

Windborn Muse and Norn's Annex are the other two taxes. Ghostly Prison costs three and makes creatures pay {2} each to attack you, and the Muse says the same for {3}{W} on a flying body, with the Annex asking {W/P} per creature for five. I keep the Prison. Norn's Decree stays too, because an opponent who deals combat damage to you gets a poison counter, which is on plan.

Grafted Exoskeleton gives +2/+2 and infect, but whenever it becomes unattached from a permanent, you sacrifice that permanent. It costs {4} to cast and {2} to equip, and moving it kills the creature it leaves. Trailblazer's Boots gives nonbasic landwalk, which does nothing against a player whose lands are all basic. Neither piece is worth its equip cost.

Scavenging Ooze is a fine card that does nothing for poison. It is a 2-drop in a deck that has nine others, and Fynn is a better one. Noxious Assault gives creatures +2/+2 and poisons each creature's controller that blocks, for {3}{G}{G}. Triumph does more of that job for one less mana. Phyrexian Rebirth is a six-mana wrath that leaves you an X/X Horror, and the list keeps Fumigate and Merciless Eviction for resets. Cutting it, with the Annex, takes the cards that need {W}{W} from four to two (Fumigate and the Choirmaster). White's source count stays at 26 and its check at 84.4%.

Two lands that enter tapped become two that cost two life

Bojuka Bog enters tapped for {B} and exiles a graveyard when it does. Myriad Landscape enters tapped for {C} and, for {2} and a sacrifice, fetches two basics that share a type. Both come out for Overgrown Tomb (Swamp Forest) and Godless Shrine (Plains Swamp), which enter untapped if you pay 2 life. Always-tapped lands go from 8 to 6.

Both shocklands carry basic land types, so the box's Snarls and its Fortified Village can reveal them from hand: Necroblossom Snarl asks for a Swamp or Forest card, Shineshadow Snarl a Plains or Swamp, and Fortified Village a Forest or Plains. Krosan Verge can fetch Overgrown Tomb as its Forest and Godless Shrine as its Plains. They aren't basic lands, so they don't count toward Canopy Vista.

The colour totals barely move. Black stays at 27 sources, green goes from 30 to 29 and white stays at 26. I wouldn't call the mana fixed: {B}{B} by turn three on the play is 76.4% before and after, and {G}{G} is 80.4% against 82.2%. Skithiryx and Vraska add two more black double pips, but they cost five and six, so by the time you cast them you've seen more cards than the turn-three figure assumes. Vraska's second black pip is hybrid and can be paid with 2 life, though that enters her with two fewer loyalty. Both shocklands get a Star Trek reprint on 13 November 2026, so their $16.56 may fall.

Eight cards I weighed and passed on

None of these is a Game Changer. Skrelv's Hive ($0.32) is the closest call: it costs {1}{W}, makes a toxic Mite at each upkeep for 1 life, and gives your toxic creatures lifelink once an opponent has three counters. The Mites can't block, and white is the thinnest colour at 26 sources, so I left it as the eleventh swap. Venerated Rotpriest ($3.17) is a 1/2 toxic one-drop that poisons an opponent when a spell targets one of your creatures, and Skrelv gives more. Atomize ($8.66) destroys any nonland permanent and proliferates at instant speed, and the box already has Mortify, Putrefy and Vraska's Fall. Contagion Engine ($12.96) proliferates twice for {4}, tap, and costs six. Staff of Compleation ($3.71) proliferates for 3 life per use. Tyrranax Rex ($5.90) is toxic 4 with haste and ward {4}, and it's a seven-drop needing {G}{G}{G}. Karumonix, the Rat King ($1.04) only helps two Rats. Temple Garden ($6.32) is the third shockland and would help white, the thinnest colour. Only two cards want {W}{W} and only at turn five, so I left it.

Nineteen creatures that poison in combat, up from fifteen

The deck stays at 38 lands. Average mana value goes from 3.26 to 3.15, cards costing four or more fall from 22 to 19 and one-drops rise from 4 to 5. Creatures go from 23 to 26 counting Ixhel. Creatures that poison in combat rise from 15 to 19, and proliferating cards from 12 to 16. The bracket floor stays at 1 with no Game Changers. The list's Scryfall total moves from $156.39 to $184.32.

The upgraded decklist

Ixhel and the 99 with all ten swaps made, sorted by card type. Hovering any name shows the card.

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FAQ

How do I get an opponent to three poison counters for Ixhel?

Four routes in the list do it in one go or close to it. Caress of Phyrexia gives a target player three counters outright (and three cards, which is its price). Venomous Brutalizer and Glissa's Retriever each hand out three on a hit. And once Fynn, the Fangbearer is out, a hit from Bilious Skulldweller is three counters by itself: one from toxic, two from Fynn.

Should Culling Ritual stay in the deck?

I cut it. It destroys each nonland permanent with mana value 2 or less, and the box has 17 of them: 11 creatures and 6 artifacts. The mana it adds goes away at the end of the phase. Keep it only if your pod is full of cheap permanents and you have a way to rebuild afterwards.

How much do the Corrupting Influence swaps cost?

The ten adds come to $50.64 at the cheapest released printing of each card. Skithiryx ($12.25) and Triumph of the Hordes ($11.31) are $23.56 of that. Overgrown Tomb and Godless Shrine are $16.56 together and both get a Star Trek reprint on 13 November 2026, so wait on those two if you can.

Can Triumph of the Hordes win the game by itself?

It can end one opponent, not the table. Two unblocked 4/4s such as Bloated Contaminator and Venomous Brutalizer become two 5/5s with infect, which is at least ten poison counters, and ten is a loss. The other opponents are untouched, so it works best when the table is already at three or four counters each.

Is Fynn, the Fangbearer worth a slot in a deck with one deathtouch creature?

Yes, because Fynn has deathtouch herself. She is a 1/3 that puts two poison counters on a player whenever she connects, and Bilious Skulldweller, the box's only other deathtouch creature, turns from one counter a hit into three.

What does the black mana look like after the swaps?

Better on tempo, not on colour. The list still has 27 black sources, and the chance of {B}{B} by turn three on the play is 76.4%, the same as the box. Two of the five spells that want {B}{B} are Skithiryx at five mana and Vraska at six, and both are cast later than that check assumes. Vraska's second black pip can also be paid with 2 life.