Rank the class up to rank 10 don't stop at rank 5
Use your first skill(Shadow Kunai) a lot
Incase you're really low on health but you don't have enough mana use the third skill(Shadow Soul) then use the second skill (Chi Heal)
The first skill(Shadow Kunai) and the 5th skill(Flaming Dragon) can have a chance to effect your opponent with "twisted dragon" which makes your enemy hit 0's on you
Since Shadow Kunai stacks, the DoT damage increases everytime you use Shadow Kunai. The Third Skill(Shadow Soul) will clear your Shadow Kunai stacks on use. You know if your Shadow Kunai stacks are gone if it says: "Shadow Kunai fades" on the enemy.
The more you use Shadow Kunai the more damage your DoTs do (My max DoT was 4000)
Some people consider this class as bad is either because:
1) They perfer another class which they like to use
2) This class uses strategy and some people don't like using strategy
3) They say this class sucks because they want classes that they can hit high damage/crits with.
4) They don't know about the rank 10 passive which increases your DoT damage by 400%