Yeah the laguz are fighting General Zelgius of Begnion and his army. There is a new wolf type of laguz as well. Sothe and his step sister, who seems to be the lord in this FE, Micaiah are from Daein. My guess is that Begnion is trying to annex Daein in its weakened state. Since Sothe and his sister are from Daein, they are probably trying to gain Daein's independence for the Begnion Empire and rebuild their shattered homeland. Supposedly, Elincia is playable as well. This is what leads me to believe that Begnion has probably over stepped their bounds in Daein. Hopefully, we can find out who the Black Knight is. A lot of players thought he was Zelgius. Maybe we will find out for certain in Goddess of Dawn.