MysticalWiki

Backstab

Rogue class' only
Backstab is a way to sneak up on a target and attempt to place your weapon
in its back at exactly the weakest spot to inflict maximum damage. A success-
ful backstab gives a damage multiplier that is level based. The chance of
successfully backstabbing something depends on how well you have practiced
backstab and your attributes. You can always backstab a sleeping target.

The classes that get the skill backstab are:

thief      : Level  20 (excellent)
bard       : Level  26 (good)
assassin   : Level   5 (excellent)
pirate     : Level  25 (excellent)
rogue      : Level  10 (excellent)