Took a while for me to figure out but I think I've finally got a hand on what the story is.
Theres a sorta duel storyline going on... Basically one is a bunch of flash backs looking back at what happened, and the other is current events. Basically, a couple years ago... the king of this empire was killed in some tragedy attack that happened on his castle (not sure on what happened yet). But somehow, his soul was saved and captured, then left in the castle. Now some corrupt cardinal has taken over and the land is at unease (its not really terrible though...)
The game starts with some mystery girl stealing the soul of the king. And the "wisp" you control is probably the soul of the king. Basically part of the time, you watch the cardinal and his cronies talking about trying to capture the girl, and the other half of the time... you follow the wisp. As the wisp, you are able to sorta half resurrect fallen soldiers you find, who u will be able to control. And after each battle, when you get a couple soldiers, you get a little look back into their past... and all of them are usually revolving around the "calamity" that happened when the king died.