There is a time-limited opportunity for the 4 starting players to increase some of their stats. There is a sensei, Shiro, in the town of Karavorks before you take a boat to the fortress. For $100 each character, you can begin the training. You do get to decide which characters you want to participate. You must pay for this training, but it is not necessary to complete the training, before you enter the Fortress.
It will take 40 uses (by each character during battle) of this “Practice Training” to succeed and get the stat bonuses. It can be done while increasing uses of other characters' skills, but it does not do any damage to the enemy. And as is usual in this game, you are limited to using the Practice Training only 3 times per 8 rounds per character. So, if you have a particularly useless character for a battle, then use the opportunity to use this skill.
Here are the results for the 4 characters:
Callaghan - +5% CRI, +5% CNT, 110% EXR
Rose - +5% HIT, +5% EVA, +15% CEV
Davy - +105% DEX, +105% STA, +45% CEV
Oscar - 105% STA, 105% AGI, Attack State (inflict?) Poisoned +15%, Attack Speed +15