Each profession has different skills and initial outfit which are attuned to their key role in the party. It is not until you have progressed past the first few levels (checkpoints) that you will be able to distinguish these roles and how different Heroes are needed to be paired with your character in order to be effective in battles.
Guard (Tank)
This character is adept at performing melee attacks and mainly servrs as the party's tank due to their high level of survivablility and HP. Guards are best positioned on the front lines as they are equipped with buffs that increase their defense and attack power.
Scholar (AOE)
This character is a heavy damage dealer that has wide ranged attacks. Scholars should be positioned at the back end of the formation regardless of its weak defense where it can play the role of the crowd damage dealer.
Imperial Medic (Control)
This character is able to deal a decent amount of damage to enemies but its main strength lies in its perk of controlling the opponents' action. The Imperial Medic is an ideal damage control type of character as it has an array of debilitating buffs that affects the flow of the enemies' movements or attacks.
Imperial Gourmet (Heal)
Although not particularly good at dealing damage themselves an Imperial Gourmet becomes a key character when they assist relatively strong heroes as they have the skills to continuously revive or instantly fulfil health during battle.