Well again it's all up to you considering my trio will be made up of 

The Big Guy/Leader: Jiro
The Fast Guy/Lancer: Zaku
The Healer/Heart: Isabelle 

Zaku and Jiro will be abnormally skilled in their particular areas but that is mostly due to the fact that both of them are vaike like in their builds. Zaku despises the use of magic and has no natural talent for it at all. Plus his lack of strength. He has made up for that by being extremely fast, precise, and deadly. Jiro has a insignificantly small amount of untapped magical talent but he has never used it nor will he likely ever will being more based around his sword and ungodly strong power attacks. What he lacks in speed, luck, and magic he makes up for by being a monstrous force of nature essentially a tank.