[@POOHEAD189]


[quote]In the aftermath of the Istvaan Dropsite Massacre, some Astartes legions have turned against the Emperor of Mankind and wage war against him. In turn, some legions remain loyal.[/quote]


So I'd assume it'd be in between the Istvaan III massacre and the Siege of Terra itself, so 006.M31 to  ‎0014.M31

That make enough sense for you, POO? :lol

[quote]among the characters I am seeing different times in the history of the Great Crusade[/quote]

I don't think you are, they're all in the aftermath of Istvaan V - the original betrayal - and before the Siege of Terra.

Minus the Thousand Son, who were carved up by the Space Dogs earlier in the timeline.