For this "serious story" we had "HEY BUCKETHEAD! "I'M CAPTAIN BASCH!" "I'm the leading man, who else?" and oodles more comedy.

Balthier's dialogue for half the game consists of pithy one-liners. Just have him bounce them off Fran during battle. Or bounce them off someone else. He's not used to being with anyone else. Have someone who won't put up with his smart talk, like Ashe.