Insidious Roots is a combo deck that's near and dear to my heart, and a number of Dusourn cards slot into it in powerful and interesting ways that allow us to upgrade the build to possibly generate more consistent gameplay.
The Core Combo
If you didn't read my last article talking about the previous version of Insidious Roots combo, here's a quick rundown. This is a combo deck designed to get a one-hit kill that the opponent will likely not see coming after comboing off with the following three cards.
Osteomancer Adept gives you an effect similar to Underworld Breach and Insidious Roots makes creatures that Tyvar, Jubilant Brawler allows to tap for mana the turn they enter. If your deck has a critical mass of creatures, you can use Snarling Gorehound to mill out your entire deck, putting a ton of gigantic plants on the battlefield in the process.
You then finish the combo with a Voldaren Thrillseeker backing up the largest plant you control (which will likely be unable to attack) and flinging it at your opponent's face. You'll note the plant tokens can only tap for mana when an Insidious Roots is on the field, but it can be any color. Given that the Thrillseeker is only good if we've gone off, I don't believe red lands are necessary in the deck.
The New Additions
Overlord of the Balemurk is one of the strongest additions this archetype could have asked for. At only two mana, it's capable of filling our graveyard with enough material to feed an Osteomancer and it also pulls almost any of the relevant combo pieces from our yard back into our hand. If the item grabbed is a creature, it can also trigger Insidious Roots, which never hurts. If that wasn't enough, it also counts as a creature in our graveyard, so Osteomancer can pull it back even if you pay the impending cost, and it can be exiled to trigger Roots.
You can think of the Overlord as a strict upgrade over Cache Grab.
The adjective they picked for Insidious Fungus means it pretty much has to be in this deck. The Fungus is a main deck-worthy disenchant effect that can also be used to draw a card and ramp, which means it's never dead in hand. It's also a one-drop creature, so it is perfect fuel for our combo engine. This also operates as redundancy with Haywire Mite, which is an effect that's very, very powerful in Standard these days.
While Insidious Fungus is slightly more expensive to play and activate than Haywire Mite, I do believe they coexisting in this deck is correct since there are a lot of powerful artifacts and enchantments in Standard right now.
Other Additions
Coati Scavenger is a card my Twitch chat has been high on for some time and I previously dismissed it because three mana is fairly expensive for this build. However, Overlord of the Balemurk is capable of milling a lot of cards quickly, so the chances of us throwing Insidious Roots into our graveyard are fairly high. I decided to take the plunge and put the Ixalan raccoon into the deck. Given how few non-permanents we're running, the Descend 4 requirement is nearly always online, making this card effectively an Eternal Witness in this deck.
Having this safeguard also gives us the freedom to surveil away early copies of Tyvar or even Roots if we need to with the understanding that we can go back for them later.
Given that we're going for a more mill-happy approach, Gnawing Vermin adds a ton of utility to the deck – more than you might think at first glance. The additional mill is welcome to help fuel our graveyard, but its death trigger means it can trade with two-toughness creatures and it can also pick off Deep-Cavern Bat if the opponent hasn't pumped it. If a mono red or Gruul opponent tees up their Heartfire Hero or Emberheart Challenger, they'll have to pump it pretty hard to survive a tangle with this thing.
Exclusions
With all good iteration comes sacrifice, and this build is no exception. We had to make a few cuts to make way for our new toys and here’s my reasoning for cutting them. As always, if you disagree with this analysis and want to run a version of this deck, feel free to bring these into your versions. As the meta shifts, these might line up better.
Harvester was a staple in the previous build because it's removal that can be a creature in hand and in the yard. Unfortunately, creature threats in Standard have gotten huge, even the ones that aren't huge when they first hit the battlefield, and -2/-2 just doesn't do much. I still have one in the sideboard in case of a convoke or soldiers match, but unfortunately, those decks just aren't very popular these days.
Cache Grab and Pillage the Bog are both good cards, but neither is creatures. Heck, they're not even permanents that count towards Descend. Given the deck's reliance on creature cards hitting the graveyard, including cards like this increases the likelihood that Overlord of the Balemurk is going to come up empty and that we won't be able to execute our combo consistently.
Honest Rutstein is another good card that lines up nicely with this deck and, honestly, I did run it in some early testing. Both of its abilities are helpful when we're comboing off, but the addition of Coati Scavenger and Overlord of the Balemurk make Rusty's return-to-hand ability far less impactful than it was in the previous build, and we have mana out of our ears with plant tokens once we get rolling, so the cost reduction isn't super useful generally either.
I like this card too, but it was at its best when we needed to draw cards we'd surveilled to the top without milling them while our deck was comboing off. I might tinker with this in future builds, but without Cache Grab in the deck to benefit from it being a squirrel or being able to combo this with food tokens, I just believed it wasn't as impactful as the other cards I included and something had to go.
Conclusion
This is quickly becoming one of my favorite archetypes in Standard and I plan to tinker with it all the way up until Insidious Roots rotates in 2026. There are a ton of great self-mill cards in Standard that could help power this deck up, and I also expect to see more as new sets are released in the next two years. The deck is a ton of fun to execute but, admittedly, it does require a ton of clicks on Arena. If you're not a fan of long sequences of actions, definitely avoid this one, but if you're a combo glutton like me, it's a hoot to play.
Thanks for reading, and happy brewing!