As a former slave, you learned how to conceal your malice toward your owner behind a facade of clumsiness.

Benefit: The first time you attack someone with an attack that deals nonlethal damage, your target must make a Sense Motive opposed by your Bluff check minus the damage dealt to realize you actually intended to harm him; failure means he believe the injury was an accident on your part instead (though he may still want to punish you for it).