[@Kazemitsu]

It's essentially a personality quirk about your character that augments and improves their abilities.

For example, if your hunter has a particularly short temper and fast disposition, you could have his attacks deal more damage. Or his attacks could have the ability to chain together into longer and faster combos. Think of it as your hunter's passive ability, based on their personality and fighting style.

You can look at my character, Tetsu Ken, for reference.