Dirty Fighting Feat now grants some Damage Bonus to the owner, based on their levels in certain types of Classes.
The Classes are as follows:
Barbarian
Blackguard
Champion of Torm
Red Dragon Disciple
Dwarven Defender
Fighter
Monk
Paladin
Weapon Master
Ranger
Harper Scout
Purple Dragon Knight
These Classes combined determine the bonus you get, based on the following calculations.
24 Levels and below get 1 Damage Bonus.
25 to 34 Classes get 2 Damage Bonus.
35 to 39 Classes get 3 Damage Bonus.
40 Classes get 4 Damage Bonus.
All Damage Bonuses are in Bludgeoning Damage Type.
These bonuses will apply to any weapon.