So i saw ppl saying that dagger mastary is bugged(dont give register any back attack), and I went testing.
found out backstab is bugged. it does no different doing a front backstab or a back one, all the same dmg and crit chance.
the skill did not say what % is a true backstab gonna increase but im puting my bet on 50% ( i remeber old time it was 50%), and im using backroll on feint to make sure i have true back stab.
front stab
back stab
the difference in dmg would be cause of min-max dmg of course.