Why wouldn't a CSM betray other CSMs? He has already betrayed his former liege and his former battle-brothers. And betrayal is a virtue in the religion of Chaos. Why would the CSMs be a cohesive fighting-force? What keeps them in line? What is the greater goal they are sacrificing themselves for? If a CSM had the choice, would he sacrifice himself to save a CSM battle-brother? Why would he? Again, betrayal is a source of psychic power in the WH40k-universe. Let a comrade die and you are better off. There is one cohesive, competent CSM-army: the Black Legion, because they don't follow Chaos, they wage the Long War. And this military campaign is the greater goal that unites them.
They were betrayed first, By the lies of this liege. And their battle-brothers protecting this liege, even after this lies were revealed. Fighting against the tyranny of the monster is not a betrayal. U know, to defeat the ultimate evil in the universe. Imperium. To protect the humanity from its degrading influence. To reveal the truth about the Gods. Yes, sometimes he would. It happened among Night Lords, it happened among Word Bearers, dunno about other legions, didnt read about them yet.
The simple answer is that Chaos is about individualism, it's about my rights, my story, my quest for power. Of course, Chaos is not actually that simple, there's much more to it. Revenge, belief in higher powers, the desire for freedom, the quest for knowledge and gratification. It's all chaos. Both more, and less. But at it's heart, I'd say it's all about the individual's thirst for freedom, no matter the cost. At least for me.
Because to some Warbands, being a blood brother means more then anything in the universe. The people who say only the Black Legion or Word Bearers are cohesive are missing a lot of key facets about the Chaos Legions. They still are Space Marines, and Space Marines are born and created to be part of something bigger then themselves, that's how it's always been. To some being part of the Legions means nothing in the 41st millennium, to others it means more then it ever did before. To countless Chaos Warbands it would be an honor to die for your brother, just as in countless others they could not care less. In fact i'd go so far as to say Bob is entirely incorrect, the Traitor Legions work as a cohesive fighting force all the time in 40k: Look at the Emperors Children during the shattering of Luggnath, look at the Death Guards plague fleet invasions, look at the Night Lords at Scounds Fall who came within 100 light years of Terra itself.
It irks me how Chaos Space Marines are seen as soulless barbarians who are only content to reave and kill, and yet once they encounter the normal Space Marines, they turns into mindless fools who seem to home in on incoming bullets. It also irks me how they rarely seem to have much more character development than "Blood for the Blood God!" I get it, they're full of rage and hatred, but there are some out there who haven't fallen completely into madness, at least I believe, and who are totally capable of feeling what we do, if not more so. It's such a multifaceted topic, it can't be easily summed up. It would be great to see the more of what makes Chaos what it is, in relation to Chaos Space Marines, as opposed to heartless terrors who are reduced to fumbling idiots once their loyalists brothers make an appearance.
The Night Lords splintered for the first time during the Horus Heresy after their defeat at the hands of the Dark Angels in the Thramas-Crusade. Then they splintered a second time after the Horus Heresy when the successor-chapters of the Ultramarines-Legion attacked Tsagualsa and the Night Lords fled rather than putting up a fight. The Night Lords warbands reunited into a single fighting force for the first time for the 13th Black Crusade, when Decimus lead them into the fight against Ulthwé. --------------------- With regard to the Iron Warriors... Aren't there multiple IW warlords fighting each other on Medrengard? --------------------- With regard to the Alpha Legion... Do we have any information what happened to them after the Horus Heresy? (Well, at least parts of the Alpha Legion fled into the Eye of Terror and they took part in the Legion Wars. Abaddon defeated them with his newly-formed Black Legion and forced them to accept him as their overall general for the 1st Black Crusade. But after that...)
