Well, in my opinion, pretty much all of the traitor Primarchs would have turned against the Emperor by themselves anyways, without any influence from their Legions, or even without Chaos. Most of them seemed to have a serious anger against the Emperor anyway, or at least the other Primarchs, and so they would have ended up doing something... or so my opinion goes anyways...
The only exception to this IMO is Magnus... poor guy... he really was loyal, just made a few mistakes, but due to Horus screwing up the Emperor's order the Space Wolves decimated them just for trying to help the big E, and at the last moment he turned to Chaos just to save his Legion...
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By trying we can easily learn to endure adversity -- another man's, I mean. - Mark Twain  |