Caravan entities shows up in Therapist, btw. As do undead. Fortress play, right now is annoying as all get out. They show up as the last wave, if ya sort by waves. My guess is he's a visiting friendly entity, on an adventure, himself. He just happened to bump into your region. And I doubt you know for sure, he's blocking other migrants, as they seem to only get reported now in therapist, once they appear. I had to refresh Therapist just this morning, because I updated it before they all finished trickling in. This is different than the past release, where we got them all reported, in one big packet of info. Now we get head counts as they roll in. *shrug*
Your migrants showing up with skills on or skills off?
I'm getting some quarky behavior, too. I've done about a dozen embarks with skills off on vanilla, well with the exception of removing all those oddball english accents. No skills is a feature I really like. And am very happy Toady included. I've found some oddities, in fortress playability with it. I will get to reporting them soon, after winter sports end. And spring fever goes away, ha.
You say your positive its the first wave? Could it be the second and him just be there as last caravan residual? If he's high in an attribute it sounds like a visitor from another civ, who. How high did you say he was? I seldom see skills over lv1 in my first wave. Does he have high military and socials, too? Good luck, Knutor