Awakening

By spending Awakening items, medals and zeni, you can permanently increase the stats of the selected character and unlock their potential. This doesn't increase the character's level and it can be done regardless of the character's level. You can obtain Awakening items and medals by tackling missions and quests. As tempting as it may seem, I'll suggest waiting until the character reached its max level so you can perform a Z-Awakening instead.