What I don't get is why didn't Ars' father take him along on this campaign to see what war is really like. He can stay behind the scenes with Rosel, and stay far away from the frontlines. At the very least, he can gain valuable experience while his dad is still alive.
Still, when his dad inevitably dies, he will have to take action. I want to see what happens then. Also, I'm pretty sure that by marrying Lycia, if she is an only child, then Ars will eventually take over her territory. As to how he will eventually take over Missian, maybe the brothers will eventually kill each other over the governorship of Missian? Then, of course, he will take over Seitz for continually invading his territory.
This brings back memories of the original Utawarerumono, which was an awesome series.