I can Not really find this AS an Post or Argument, because I want to Ask, why do so many people think Dorn would Just Join one of the two?
They could do Something Like with the Ynari, letting Dorn have His one Mixed forces Army or letting him BE Played in both Armys.
I have two reasons why I think this
Dorn Made the last wall protocol, which made all Imperial Fist chapters regroup into the Main Legion / chapter. Why would He Not do that again to fight again, but knowing His forces are Split and fight at strategic Point, and taking Just Part of them and building His Demi Legion / chapter to fight with him.
That would BE Like the Same thing Like Ynari in some way.
Also why would GW Not Take the Chance to get more Money, which IS Not even lore friendly and no people would complain about it. Because IT would make Sens.
And with Perturabo next to BE confirmed to BE the New demon primarchs maybe, with a Bug force, wh Not get Rogal Dorn to let to giant Fight each other
PS: Sorry for the grammatic and other Error in writing