backstab 'dual backstab'

Thieves learn this skill early in their lives, to prepare them for the hard road of stealing and hiding ahead. It allows the thief to deliver a powerful stab to the back of an intended victim. It can only be used on those who have not been hurt badly, otherwise their intended victim will be too cautious for such an attack. Dual backstab works much the same way, and is a higher-ranking thief skill, allowing the thief to deliver two strikes to the back.