So, based on what we know about this guy, how would he react if one of his sons had managed to forge a significant stellar empire before he reached him, one that was scientifically flourishing and included a whole bunch of tightly-knit alien council races/allies/whatever? Not a handful of sectors here, but something that would look significant on the galactic map, like around half the size of the current Sautekh Dynasty?
Also, not hostile or "hhghhh fuk u dad my way is better" toward the Emperor. Instead when he meets this Primarch they're enthusiastic as fuck and just assume the Emperor's vision is like theirs, and are completely ready to start putting this domain's resources and armies to use in defeating the enemies of order and civilization.
Would this be something he'd try to contain? Try to destroy? Cautiously give the thumbs-up for?
He would love and cherish them, just as he did with most of his sons (before the current cadre of Black Library writers fucked up his character)
>>54720909
[REDACTED]
Launch massive propaganda campaign declaring the Xenos in his council as good Xenos while every other Xenos is bad Xenos.
The Emperor is not a man of principles. He does what is needed to ensure humanity's progress.
>>54720909
As long as the Xenos aren't posing a dire existential threat to humanity at large, he'd declare them sanctioned xenos and start incorporating his Son's empire into the Imperium as closely as possible.
Otherwise, there will be a lot of arguing, followed by a Crusade.
>>54722113
I mean technically he is a man of principle, but said principle is humanity's progress
>>54720909
The emperor and imperium are only anti xenos out of necessity. Even "peaceful" xenos like Eldar and tau pose huge threats. Any xenos beneficial to humanity would have absolutely been tolerated and sanctioned. The emperor even tried to start alliances before being backstabbed every time so he just said you know what I don't have time for your bullshit and just obliterated them
>>54722113
>>54722711
These two things.
>>54720909
Either, he takes one look around, gives his son his Space Marines, and sends them to the other side of the galaxy while he genocides all the aliens in his son's empire, or he goes "okay, but first we'll need to kill all the aliens," and then makes him stand there and watch while he does so.