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Warhammer Underworlds

The Impact of Deadly Synergy in Warhammer Underworlds

by Jake Bennington | Dec 17 2025

Welcome to another installment of Starting Hex, a series about Warhammer Underworlds. Deadly Synergy, one of the two new decks released in the Spitewood box, has been in the wild for a few months now. While most of the decks released individually since Embergard's release have found mixed success as they settle into their niches, Deadly Synergy stands out as being a solid option from the day it was released and it has been utilized by a variety of warbands and various deck combinations in Nemesis.

Using last month's event held at the World Championships of Warhammer as a reference, Deadly Synergy was among the top three decks chosen by competitors alongside the edition-long staples of Blazing Assault and Pillage & Plunder. You can check out the specific numbers and far more details breaking down the event over at Spent Glory.

Given that so much of this deck's scoring and potency relies on fighters being united and leveraging the flanked bonus, any mechanics that can interact with those states have been impacted by this deck's prevalence. It's made some cards or abilities less effective while also providing extra benefit to some existing tools. Let's take a look at how this deck is shaping the meta and examine ways in which you can try to get ahead of it by utilizing various options in other decks or brought by a warband's warscroll.

An example of how flanking can work with Deadly Synergy. Kainan here is flanked despite only being adjacent to Kro-Jax. Credit: Jake

Approaches Weakened by Deadly Synergy

There are also some things that have gotten more difficult to use just due to the fact that Deadly Synergy exists. In my experience, chief among these is the Wrack & Ruin objective Alone in the Dark. I've been quite unhappy to draw this card in every match up I've had against a Deadly Synergy player to the point that I'm not sure it's worth taking anymore. A Deadly Synergy player doesn't have to consciously play around this objective – their entire deck just does it naturally. It's been quite frustrating to try and engineer scenarios to score this when I have it in my hand and my opponent keeps clumping up their fighters not because they're trying to play around Alone in the Dark but because that's just how they score half a dozen of their own objectives.

Alone in the Dark becomes more difficult to score just from Deadly Synergy existing while Closed Down makes it more dangerous to stand on treasure tokens. Credit: Jake

There's also a slight hit to any strategies that involve interacting with treasure tokens simply due to the existence of Closed Down. For any game approaches that involve standing on treasure tokens, even if it's just temporarily to delve them, you make it much easier for your opponent to score this juicy 2 glory objective. If you are able to play your entire gameplan without touching a treasure token, it makes the Deadly Synergy player have to commit far more resources into scoring Closed Down. This isn't necessarily enough to discourage Emberstone Sentinels, Pillage & Plunder, or any of the flex plans out there but it's something to keep in mind.

Approaches Strengthened by Deadly Synergy

The plot card for the deck states that if the Deadly Synergy player's friendly fighters are adjacent, then they're able to confer the flanked status to any adjacent enemies – this makes it much harder for the Deadly Synergy player's opponent to avoid being flanked. In fact, this is one of the main strengths of Deadly Synergy and allows the deck's pilot to make their fighters both more accurate and more durable.

A united Briar Queen realizes that it still hurts to get smacked down by Thomas's Shadeborn. Credit: Jake

Fighters with multiple save or attack dice pick up a solid boost when they're united and being attacked by an adjacent enemy. A prime example are the seven ghosts of Thorns of the Briar Queen. While their fighter cards say they're on 2 dodge, if the Thorns player is able to keep them united and count flanks as a success, it's more like being on 2 shields which is a save profile reserved for the most tanky of fighters. Counting flanked facings on the dice as successes increases the success chance on each individual dice by 16.6% and by rolling more dice, this stacks up even faster.

Offensively it's the same, effectively turning the typically inaccurate swords attacks into hammers and hammer attacks into homing missiles.

Find out if the odds are in your favor. Credit: whudice.com

If you want to see just how effective it is to increase a roll's success chance, head over to whudice.com and plug in some sample attacks with and without flanked being a success. Just as an example, a 2 hammer attack into a 2 dodge save will give the attacker a 44.4% success chance. If the defender also counts flanked as a success, the overall rate drops to 31.2%. If instead the attacker is the one benefiting from flanked and the defender isn't, the attack's success chance jumps to 59.3%. These are substantial changes in the expected outcome of attacks and saves.

Tools Effective Against Deadly Synergy

As mentioned above, the strength of the plot card in this deck is substantial. If you're playing against Deadly Synergy, then finding ways to bypass this benefit does a lot to take the wind from the deck's sails.

An effective way to avoid the defensive bonus is to simply not attack while adjacent. Using fighters with range 2+ attacks and taking weapon upgrades with similarly extended ranges allows you to position your fighters outside of adjacency which keeps the flanked result on your opponent's dice from being a success. Aggressive warbands like Gorechosen of Dromm and the Shadeborn have most (or all!) of their fighters threatening to deal damage at range 2 while ranged attack heavy warbands like Thundrik's Profiteers and Ephilim's Pandaemonium can stand even further back to pepper the enemy with ranged attacks. Even warbands with mixed profiles like the Emberwatch or Ylthari's Guardians can choose their lower damage but higher ranged attack options to increase their accuracy while staying outside of the reach of the flanked state.

Linebreaker and Assured Bloodshed are both ways to gain Brutal, but at the cost of one of your valuable power card slots. Credit: Jake

Another offensive way to deny the flanked status is by taking advantage of the Brutal runemark. As an accuracy booster, I've been valuing Brutal lower than either Cleave or Ensnare for most of this edition. I still don't think it's going to be worthwhile to take an upgrade like Linebreaker that only gives you that runemark, but other options like Assured Bloodshed exist which offer slightly more utility. There's also a few warbands that have Brutal baked into some of their fighter profiles. Some terrifying examples are inspired Sepsimus from the Wurmspat, inspired Gorl from the Gnarlspirit Pack, Mollog all the time, and inspired 'Ardskull from Morgok's Krushas. These are all 3 damage attacks that ignore the defensive aspect of Deadly Synergy. As an additional point in Brutal's favor, it's also going to deny the defensive effect of cover tokens for your opponent which can come in handy against another popular deck Pillage & Plunder, among other match ups.

As far as ways of denying the flanked (or surrounded) status go, Blazing Assault has a leg up here with its Brawler upgrade. Turning off the ability of your opponent to flank one of your fighters helps to blunt their accuracy and boosts your own at the same time when brawling with enemy united fighters. Inviolate from Emberstone Sentinels can pull a reasonable impression of Brawler provided your fighter is on a treasure token. Some warbands have built in flanked denial such as the recently released Kurnoth's Heralds (in their own territory at least) and the Brethren of the Bolt (when that option is chosen from their Fulminating Hymn -- and remember, this effect doesn't end at the end of the round!).

Both of these Reckless Fury cards become easier to activate when your opponent is clumping up due to their own Deadly Synergy incentives. Credit: Jake

You can also take advantage of the fact that the Deadly Synergy fighters are often going to be clustered up. It makes objectives like Vicious Brawl from Reckless Fury and Diving In from that same deck more reliable.

Being able to prevent drive back can be handy in denying the aforementioned Closed Down as well as Outmuscle. These are both 2 glory objectives that the are commonly seen in Deadly Synergy Nemesis decks. Cards that give out guard tokens like Shields Up! from Blazing Assault, Settle In from Emberstone Sentinels, and Wary Delver from Pillage & Plunder will pick up additional utility in match ups against this deck. Likewise, any warscrolls that can hand out guard tokens including Morgok's Krushas, serve double duty. Guard isn't the only way to avoid drive backs, either. There's also Obstinate from the Jaws of Itzl warscroll, the infamous Phantasmal Forms from Elathain's Soulraid that allows Fuirann to always use Stand Fast, and The Bulwark Celestial from the Starblood Stalker's warscroll. Speaking from personal experience as a BA/DS player, it was incredibly annoying to sit down across from a Starblood Stalkers player and have them be immune to drive backs for what felt like half the game while both Closed Down and Outmuscle stared at me in my hand.

Final Thoughts

Credit: Games Workshop

Deadly Synergy has quickly made a name for itself as a potent deck in the pool of other Rivals decks in Warhammer Underworlds. It's a refreshing change of pace to have a deck show up and make an immediate splash without feeling overpowered. This is no Reckless-Fury-on-release with multiple ban worthy cards, but it's still able to hang with the heavy hitters of the game. I'm hopeful that whatever comes next is of the same caliber as Deadly Synergy and feel like further releases like this would be healthy for the game. Just… maybe hold off on making it a strike deck, GW. The people yearn to stand on treasure tokens.

Speaking of being united in synergy, I'd like to brag about how my wife and I have been together a little over 22 years now. She's awesome. That's all. See you all next week for more Underworlds musings!

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Tags: warhammer underworlds | Starting Hex

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