Instead of the obvious "save the world" storyline, Celestian Tales gives you six different characters to choose from, all of whom are nobles learning about their responsibilities to the world just as war is breaking out.
Despite the diverse cast, Tales' replay value is lower than you might expect since you learn most of the story's twists in one playthrough. That being said, there are some solid changes to the formula — such as picking between different primary and secondary skills — on display that make Celestian Tales worth playing.
The real draw here is in the interactions between the large cast of nobles working their way into the military, as each has a radically different viewpoint and reason for joining the ranks. There's a religious fanatic getting out into the wider world for the first time, a timid but rational atheist who tries to overcome problems through reason, a happy-go-lucky elf who has never experienced the savagery of war before, and more.
As you might imagine, those characters clash strongly as they are forced to work together. The end result is something quite a bit different than your average JRPG.