cs - critical strike
ds- deadly strike
one or both of them give chance to do double damage i think. Venom cancels out both of them... don't know why, maybe it's be too powerful if it didn't. Also you need to cast fade to get the 1%dr per level and I'd suggest putting rest of points into claw mastery, as it adds to attack rating, which is always useful, and it adds physical damage, which is helpful and very useful for people with good psn resist/ length reduced, like palas using guardian angel have easy 90% psn there....