40k Chaos Marines

These are all the Warhammer 40k Chaos factions

By Nicholas James


Apr 7, 2023

Reading time: 5 min

Warhammer 40,000 is an enormously popular tabletop wargame that extends out to video games, books, and more. As it gains popularity, gamers want to know what the Warhammer 40k Chaos factions are. Here’s everything you need to know to get started.

Chaos is the name for the forces within the galaxy that serve the mystical forces of the parallel dimension known as the Warp. The Warp is a reality that overlays physical reality and is affected by living beings’ emotions and thoughts. Strange beings, forces, and even gods reside within this twisted hellscape. They seek to invade, corrupt, and overpower the physical reality of the galaxy, doing battle in realspace with a variety of twisted forces.

These are all of the Warhammer 40k Chaos factions, explained for you. If you’re interested in the human Imperial forces or all the alien Xenos in the game, check our our articles on both!

Warhammer 40k Chaos factions

Chaos Space Marines – Heretic Astartes

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If you’ve read our excerpt on Imperial Space Marines, they are very similar in many ways. Just like their loyalist foes, 9 legions of the empire’s Space Marines turned traitor in a civil war 10,000 years ago. Those nine legions each represent a specialized style of warfare or devotion to Chaos that separates them from their peers.

2nd Legion – Emperor’s Children

The Emperor’s Children are devoted to Slaanesh, the Chaos god of excess. They pursue a twisted ideal of perfection and wield strange and archaic weaponry. This includes sonic weapons wielded by their signature Noise Marines, and all sorts of twisted sorcery.

4th Legion – Iron Warriors

The Iron Warriors specialize in siege warfare and battles of attrition, breaking down even the strongest foes and most secure fortresses. They are the ideological opposites to the Imperial Fists, their loyalist mirrors, and tend to use hulking demonically-possessed machines called Demon Engines to do battle for them.

8th Legion – Night Lords

The Night Lords are twisted ambush and guerilla tactics specialists. They take grizzly trophies from their enemies and focus on disrupting enemies with rapid and unpredictable strikes. They often have their aesthetic and at demeanor described as being like ‘evil Batman’, and that’s not an inaccurate way to think about it.

12th Legion – World Eaters

The World Eaters are frightening berserkers who devote themselves to Khorne, the Chaos god of violence and combat. They’re almost entirely melee-focused, preferring to get up and close with their enemies rather than do battle at range. If you like berserk melee and brutal close combat, the World Eaters are for you.

14th Legion – Death Guard

The Death Guard are corrupted and diseased Heretic Astartes who are devoted to Nurgle, the Chaos disease of sickness and plague. Slow, predictable, and incredibly durable, the Death Guard are akin to a horde of undead plodding across the battlefield to exact their pathogenic due.

16th Legion – Sons of Horus/Black Legion

The Sons of Horus were at the center of the critical civil war known as the Horus Heresy that began the unraveling of the Imperium of Man. In the ten millennia since, many of the surviving members now follow Abaddon, the once-second-in-command of the leader of that civil war. This faction is now known as the Black Legion and is the main bulk of Chaos’ forces when it comes to heretic marines.

15th Legion – Thousand Sons

The Thousand Sons are the most magically powerful legion of Space Marines, focusing on absolute magical prowess with psychic magic. Many of them lost to a curse that turned them to dust, these powderized marines serve in automata-like soldiers within their once-armor. Thousand Sons’ main distinguishing trait is their focus on psychic magic and association with the Chaos god of change and fate, Tzeentch.

18th Legion – Word Bearers

The Word Bearers are the fanatically religious legion of Heretic Astartes. Always zealous in their religious beliefs, the Word Bearers were turned to serve Chaos more generally than any Chaos god. The Word Bearers tend to specialize in sowing worship of chaos and feeding the dark powers more than any particular avenue of warfare.

20th Legion – Alpha Legion

The Alpha Legion are experts of secretive warfare and manipulation, obfuscating information and manipulating data to confuse their foes. Are they actually traitors or just loyalists deep under cover? If the Alpha Legion has you unwrapping a mystery wrapped in an enigma surrounded by a riddle, that’s about par for the course.

Chaos Demons

Chaos Demons 40k

Chaos Demons make up the majority of Chaos’ forces, and tend to be divided by their allegiance to one of the four great Chaos gods. Each of these ‘gods’ has a different domain, aesthetic, and playstyle on the tabletop.


Khorne is the Chaos god of combat, warfare, bloodlust, and everything in between. The Blood God detests psychic magic and prefers glorious melee to any other style of warfare. His demons tend to reflect that anti-psychic, pro-brawling theme in both lore and playstyle.


Slaanesh is the Chaos god of excess. They are the physical manifestation of “too much of anything is a bad thing.” Slaanesh was created by the Eldar, and caused their society to fall apart after she consumed most of their souls. Slaanesh tends to focus on speedy, glass-cannon units that do tons of damage.


Tzeentch is the Chaos god of change, fate, and trickery, and tends to focus on psychic magic. His demons tend to be unusually slippery, or capable of unexpected feats of flexibility. Tzeentch is unpredictable and wiley, and that’s reflected in a magic-heavy playstyle with lots of options.


Nurgle is the Chaos god of sickness, disease, and plague, as well as life and death. Nurgle’s twisted diseases are viewed as gifts and wonderful boons by his demons. They desire nothing more than to share “grandfather’s” gifts with the worlds of the galaxy. On the tabletop, Nurgle is slow but incredibly durable. Nurgle forces tend to want to force their opponents to come to them.

Chaos Knights

Chaos Knights

Chaos Knights are the chaos-corrupted mirror of their loyalist cousins, the Imperial Knights. They are still big stompy robots piloted by certain lineages of humans that follow knightly noble familial orders. But the Chaos Knights also have a touch of dark magic to them.

Chaos Knights are terrifying machines of war that sow carnage and chaos wherever they go. On the tabletop, Chaos Knights is super-elite army that plays with few, but individually powerful models.

Those are all the Warhammer 40k Chaos factions. Check out our other guides to the Xenos and Imperial forces of the game.