I've heard on that forum that mercenaries will desert if you are at war with their place of origin. If I've hired mercenaries at Marauder base, who shouldn't I start a war with (to keep them) - that particular Marauder lord, any Marauder lord or the Gremak empire?

to who can pay them the most in the end.

I'm surprised none of the developers had answered the very specific question.
Declaring war to the Gremak didn't cause my mercenaries to desert the next turn. Don't know if that even implemented yet.
Anyway, mentioning on the mercenaries ship info screen which faction they are originated from would be very helpful. The color and the shape aren't enough.

I don't think mercenaries are loyal to anyone but their paychecks. It sort of explicitly states they're shady underworld characters.

Currently, mercenaries are loyal and don't pay any attention to reputation changes with the source faction after they are hired.

Arioch wrote:Currently, mercenaries are loyal and don't pay any attention to reputation changes with the source faction after they are hired.

Thanks for the clarification.