From
The Locus Inn - Skill System (individual paths, and a skill table for each class)
You can get a level of one of them (random) as a quest reward. I didn't really find them nessisary, but if you have spare skill points they do help.
Augment Damage (Passive) - melee only
Through magical methods you gain the insight and knowledge of master warriors and do more damage to your opponents.
Level 1 Every succesful hit gains a 1+2 bonus in damage. Required level is 1
Level 2 Every succesful hit gains a 2+4 bonus in damage. Required level is 7
Level 3 Every succesful hit gains a 4+6 bonus in damage. Required level is 13
Level 4 Every succesful hit gains a 8+8 bonus in damage. Required level is 19
Level 5 Every succesful hit gains a 10+10 bonus in damage. Required level is 25
Augment Defense (Passive)
Your knowledge of self defense is enhanced, thereby reducing the damage sustained from your enemies.
Level 1 Armor gains a 10 percent boost. Required level is 5
Level 2 Armor gains a 20 percent boost. Required level is 11
Level 3 Armor gains a 30 percent boost. Required level is 17
Level 4 Armor gains a 40 percent boost. Required level is 23
Level 5 Armor gains a 50 percent boost. Required level is 29