Hardened (3.5e Trait)
From D&D Wiki
Your emotions have been torn from you by some tragic event of your past, or you went to an illegal military combat school where you were forced to learn not to feel emotion through brutal training.
Benefit: Any attempt to perform Intimidate, Disguise, Bluff, Sense Motive, Diplomacy, or any other form of emotional charm take a -3 penalty. You gain a +3 bonus when using Intimidate, Sense Motive and Skill.No one can read your emotions, you are not effected by emotions, you do not even feel emotions. You are the perfect warrior. A heartless, clod blooded killer.
Drawback: Due to your lack of emotion you recieve a -2 when attempting to perform the Diplomacy and Gather Information.
Roleplaying Ideas: You were a student at an illegal militaristic warrior school, where your emotions were brutally trained out of you, or perhaps you suffered a tragic accident and have lost all sense of emotion since.