Why to make one more enemy at your doorstep then you can live with it. Ech? But don't understand it wrong. Respecting something is not worshipping. Now why nomads are less agressive against them? Well, one of the theories would be (as I red in the vanila developer side notes left about nomads) is that DK left Malta for nomads. Cardamine is one of key components which changes DNA therefor helps lil baby nomads (which they are now) to envolve. Yet to efficiently use the cardamine, nomads needs to evolute quite a way themselves.
Outcasts use the drug. Their DNA is changed already into the similiar way Nomads would change most likely (same evolution might have diffrent effect on humans and nomads). That's why nomads recognizes them as, well, lighter than rest of the humanity.
But I don't know. In the end I imagine outcasts should be wiped out once Nomads would want to take over whole of the cardamine resources once they evolute to the way they could use it for themselves. Or maybe humans and Nomads might live in peace? who knows? There is one thing known - outcasts might have the key to answering this question.
Now couple of tips. Outcasts are kinda supremacists. Means .. well they think that they are better than the rest of the humanity due cardamine dna change.
Jameson (leader of 101st) is the guy who has the biggest weight about entire oc npc faction and you should listen to him or atleast don't make him mad.
OC capitals are banned from some of the places by OC commonwealth themselves. (not sure about other houses, but about liberty - there are no doubts)
Also. Outcasts are neutral with Bretonia. (Not allied)
