From the description I see something that can easily confuse the reader for the specific feat :
It sais "Your exacting precision, accuracy and control allow you to make deadly attacks against foes
who are not ready for you.
I do not think that you can add this "stacking" 1d6 to every single attack the character does in every round. Since the descriptions specify "to those who are not ready for your" it means, I guess, that it can only be used in cases similar to the rogue's sneak attack which means only when the opponent is flat footed or flanked ect.
"Benefict: When making a finesse melee attack, you gain +1d6 points of
Sneak Attack damage.
Also since the 1d6 stacking damage is explained as "sneak attack" I think it is subject by the "sneak attack" rules.
The whole feat would be insane powerfull if it wouldn't have such restriction simply because at high levels and I will make a simple example :
Thief level 15 : he has 3 attacks , and his total damage having this feat will be , 8d8 + 6d6 + weapon damage.
First 8d8 is the normal class sneak attack and 6d6 is the Master Fence feat taken 6 times (easily obtainable at 15 lvl) so medium damage number will be 32 + 18 = 50 damage without counting weapon damage. Since in Conan there is the rule of massive damage , the opponent should roll a 10+ 25 = 35 fort save or die at least without considering the weapon damage. I think there is something wrong about this

and he can do this 3 times per round .