Board Thread:Warhammer 40k General Discussion/@comment-37.152.33.225-20131111163502/@comment-96.237.238.119-20131218022151

I'd place a bet on the idea that the Imperium in its current state welcome the return of a Primarch (regardless of which one it is). That said Primarch would likely be a boon against any one of the major threats the Imperium is facing (Logan or the Lion fighting against Chaos, or Corax and Khan against Tau, etc). The populace of the Imperium (esp. the Ecclesiarchy) would also be ecstatic of the return of such a legendary hero(s), having an effect similar to the finding of an intact STC for the Mechanicus. Though I rather doubt it would happen (as most of the Primarch's were military leaders, not scientists), they COULD give some insight into the workings of the Golden Throne or attempt some kind of communication of the Emperor, though that'd be a longshot at best.

Of couse, this IS 40k, so things would probably turn shitty not long afterwards. Such as the Inquisition or the Lords of Terra growing suspicious and fearful of the Primarch's power and attempt to somehow 'eliminate' them so they do not threaten their power. The Primarch in question could also become disgusted with the state of the Imperium and attempt to change it, thereby becoming a heretic and most likely starting ANOTHER civil war within the Imperium.

All in all, I'd bet the return of ANY Primarch would initally start out great, but then wind up making things worse. ( Just like they usually do in 40k :P )