[neferhet]

in the old fluff, you could worship the whole pantheon without committing too much to any of the four or you could just sell your soul to one and consacrate your life to him. Up to the 3rd codex, the undivided crew was the most numerous ,organized and mentally stable. Then, with 5th edition, you basically HAD to choose a god and chaos undivided was almost obliterated from the records.

 

[neferhet]

Keep in mind that chaos undivided can also mean not dedicating yourself to any of the gods.

as per the new fluff i think undivided is just absence of dedication

 

[neferhet]

Similar thing with Perturabo who somehow managed to convince all 4 gods to make him a daemon prince on the back of sacrificing a few hundred Imperial Fist geneseed. The source for this is Index Astartes I which I know isn't that current but since it's not been retconned yet it's still the most up to date info on how Perty managed to ascend.

The Gods had some hot deals back then. Good times.