I have a suggestion too, why not, after the game ends, it continues and you are a lord of the kingdom serving your brother and (not a marshall) you can see the old king in prison with the grand thief and your relation with the king is 50 or so (since it IS your brother), and also, you own a castle or so..........Also, when I started playing, the two main kingdoms were at peace, this was really stupid..... As for "He brought peace to all the kingdoms", why not just forget about it?
Sorry for my grammer, I am not from a place where everyone speaks english (Everyone speaks Japanese).