First of all, if Rebirth is the final mission, this is not a technical issue, but jsut plain confusing. However, it seems there should be *more*.
I played through Rebirth, the final chapter of the 7th era, 3 times - the first time it was unclear what I had to do (free the the guy != kill the other guy... I could have used a better explanation in the presentation) and I lost because i just sent all my guys around the map and the critical guy died. Second time, I found some armies that spawned south of the castle and killed them, after which I guess I won because my armies afterwards killed the guy in the castle, which again, was not clear that they should or even that they did! After second try, I got the win-screen and a voice said "We're in!", which I later realized is supposed to be your clue that I can kill the guy in the castle. Third try, I killed everyone and did not realize that I could kill the guy in the castle, restarted, got to the same point and accidentally moved my curser over him and it turned into a stabbing-icon. Then I got the kill and kinda understood why I won.
But the MAIN THING is: I don't know if that was the last mission? Maybe because it felt unfulfilling with all the confusion and lack of core gameplay, but also because there is a blacked-out 8th icon in the mission-select screen! I am not progressing and I have no idea if that's because I'm done or what? It seems like there should be a proper ending... and I read somewhere that the Wildlings should appear, which they haven't. Serious bug then!