I have been trying to keep Talon's stats pretty even, but lately his defense numbers are kinda out of whack with the rest. Are there any stat boosters that only boost the defense?

You can find a link for the complete list of boosters here. You could also put your exp gained from battle quests into defense only until you are at the stats you want to be at. This will be the cheapest sand easiest option.

Thank you for the help and info :)