Yes you recruit the other origins. But will the personality ai (like in DOS where you could assign a personality to your 2nd character) be active?
So if I recruit the red prince and my main character talks to the recruited red prince. Will the red prince AI kick in?
I don't know... but the impression I get is that the origin is its own AI, and you can't have an "Red Prince origin + knight AI" or "Red Prince origin + rascal AI" or "Red Prince origin + psychotic AI". Just "Red Prince AI". If you have a "Generic" origin, you might get to pick an AI for if you're controlling someone else, but it might also be tied to the personality tags you can select.
But again, I do not know, that's just the impression I have.
Companions in D:OS 1 did not have an AI personality, they had specific reactions locked in. Only the two main characters, the Source Hunters had AI personalities. I think origin-companions would work very much like D:OS 1 companions.
When I kill a lizard will the recruited red prince get angry and come talk to me (or worse fight me)
Any random lizard? Probably not. A specific lizard which the red prince has a goal to keep alive? Probably still not a fight to the death, but it's much more likely to make him upset.
