# Hammer of Math: Chaos Space Marines

Primaris Kevin is back! After taking a month off to welcome a new baby girl into the world, he’s back with a look at some of rules and effects in the new Codex: Chaos Space Marines.

First of all, I can’t thank Rob enough to covering the last few articles for HoM. His work, and that of the rest of the 40k Stats team, is amazing. In the time I’ve been gone GW has dropped a ton of cool features and things for us to look over, including totally reworking how competitive play handles Command Points and just this week we’ve seen the Ruinous Powers summon forth a new Codex for their chosen sons. And boy is this book a big one. With rules and abilities for a huge number of Traitor Legions, lots of awesome Relics, and a completely re-tolled Abaddon the Despoiler there’s a lot to dive into here.

## Let the Galaxy Burn

Previously a Stratagem, now every Astartes who has sworn themselves to Chaos receives the blessing of Let the Galaxy Burn, an army-wide bonus that has two effects. The first is that flame weapons automatically score an additional 2 hits. The second is that any unmodified hit roll of 6 for an affected weapon will score 2 hits instead of 1. The affected weapon depends on the battle round and which wanton act is being performed, with later rounds focusing on shorter ranged weapons and melee combat.

In terms of mathematical impact the effect of getting a second attack on a 6 is a flat 17% improvement in output. Looking at the average number of hits it’s the equivalent of getting +1 to your ballistic skill, even if that BS is already 2+. For your typical 3+ BS model this improvement takes the average number of hits per attack from 0.67 to 0.83, which is in between the average from being able to re-roll 1s (0.78) and re-rolling all misses (0.89). Unlike modifier based abilities such as the loyalist Combat Doctrines this bonus is constant (meaning it does not depend on the target) and is universally applicable.

## Marks of Chaos

Codex: Chaos Space Marines follows the process of other modern army books and includes unit upgrades that can be purchased using points or Power Level. In this case the bonuses are Marks of Chaos, signs of devotion to one of the four Chaos Gods which provide different boosts depending on which of the Ruinous Powers is selected. Each Mark of Chaos costs 15 points (or 1 Power Level) and can be applied to multiple units in the army. Units which have the ICON keyword (obtained by spending 5 points for a Chaos Icon) get an added bonus.

The Mark of Slaanesh is the easiest; if the unit starts the Fight phase within Engagement Range of an enemy unit then it fights first. ICON units add 1 to the hit rolls of melee attacks; the impact of improving the hit roll is seen in the chart below. For melee oriented units this is a pair of logical and easily applied bonuses.

The Mark of Khorne is heavily focused on melee. The unit gains +1S on melee attacks if it charged, was charged, or performed a Heroic Intervention. ICON units also improve the Armour Penetration of their melee attacks by 1. The bonus Strength is situational and requires that the characteristic pass a threshold in order to modify the wound roll, while the Armour Penetration is also dependent on the original value (as well as whether the existing AP was sufficient to overcome the target’s Save characteristic). A good example of how situational this can be can be found in a unit of Legionaries attacking some loyalist Space Marines. The bonus to Strength means they’re wounding on a 3+ instead of 4+ (25% improvement), but due to Armour of Contempt their unarmed attacks would be no different while attacks with a chainsword would reduce the save from 3+ to 4+ (in other words the chances of breaking the save would go from a 5+ to a 4+, a 33% improvement). Assuming a chainsword is carried (and what respecting worshipper of Khorne wouldn’t?) the result would be a 67% increase in attacks that would go through the wound and save checks.

The Mark of Tzeentch offers both offensive and defensive bonuses. In defense the first time a saving through is failed each turn the Damage characteristic of the attack is changed to 0. ICON units get a bonus AP to ranged attacks. In contrast to the Mark of Khorne the defensive bonus is universally applicable, although players are encouraged to be careful about choosing the order of their attacks and saves to ensure that the effect is exploited as much as possible. For the ranged attacks the AP bonus is the same as the Khorne situation, although in general Astartes weapons have some sort of penetration to start with.

The Mark of Nurgle is an interesting one. The first part is extremely specific; against attacks that have a Strength characteristic equal to the target’s toughness (attacks that wound on a 4+) or equal to or greater than double the Toughness characteristic of the unit (attacks that wound on a 2+) you subtract 1 from the wound roll. To be honest I genuinely don’t know why GW decided to go this route instead of making it a miniature Transhuman Physiology effect that ignored unmodified wound rolls of 1 or 2, but this does offer some slight advantages in those situations where you’re being attacked with a S4 weapon. For the most part it’s the same as having Toughness 5 on your units until you hit S10+, at which point you’ll only be wounded on a 3+.

Rob: We’ve corrected this from the initial version, which suggested -1 to wound only occurred when the attack was “equal to double the target’s toughness or more.” For what it’s worth, I think the reason they went with this is to have a Mark of Nurgle ability that can stack meaningfully on Plague Marines – when you add a Plague Marines unit to a Chaos Space marines army, it gains the Mark of Nurgle, and from that point will only be wounded on a 5+ by attacks that are S5, and on a 3+ from attacks that are S10+.

The ICON ability for the Mark of Nurgle is that hit rolls of 6 always wound the target for ranged attacks. This ability is universally applicable but the effect is dependent on the wound roll; 1/6 of the time the probability of wounding the target is 1 instead of the original value. The chart below shows the impact. Note that the Mark of Nurgle bonus does not stack with Let the Galaxy Burn; the bonus hit does not count as having any kind of hit roll value and so would wound as normal.

## Beseech the Dark Gods

Much like the powers and temptations of Chaos itself, this article only scratches the surface of the potential offered by the new book. Don’t be surprised if we come back to look at other areas such as Legion traits, the trials and tribulations of killing Abaddon, or how many mortal wounds you can achieve if you really put your mind to it. If you have anything you think would be a good topic, either use the e-mail address below or if you’re a Patron feel free to reach out to me on our Discord server.

Thanks for reading! If you have any questions or comments feel free to drop us a note in the Comments below or email us at contact@goonhammer.com. That’s also the best way to suggest topics for future articles.