He has never felt guilt.
He knows what it is, has read of it and heard it described. A sick feeling in your stomach, a jolt of remorse that strikes deep down to your very soul. A crack in a soldier's armour, the chink in his chain, the chip in his mask. It is powerful, unshakable, a feeling that never really leaves you, and if you let it, will consume you utterly.
But he has never felt it.
The first time he sees it (that he remembers and understands) he is six, and his teacher has just hit him (not a first) after he asked a question too many, the final straw on a stressed young woman's back. It sparks first in her eyes; realisation and horror and howcouldIdothat? She drops to her knees, cradles his face in her hands (it doesn't even hurt, not really. He's felt worse), and he ignores her words (I'msorryI'msorryohgodareyouokaysorrysorry) and instead watches her face. He sees the way the guilt overshadows her previous irritation with him, changes the way she sees him completely (a hurt child, just a little boy, not the unnerving not-child who is too smart and cold and abnormal). It effects her far more than fear or affection could.
Why is that?
People feel guilt because they do something that goes against their own personal morals, as he understands it. A serial killer would not feel guilty for another murder, yet different man would be crushed beneath its weight. However, if that killer was to do something that went against their own set of ethics, twisted as they may happen to be, he too will be consumed.
People hold themselves to a certain standard, blinker themselves with guidelines and rules of what is right and wrong. And they do their best to follow this code, to adhere to it, and should they stray from this then they punish themselves with guilt. Why bother with torture when one can so effectively do so to themselves?
People are...he thinks, watching a soldier as he falls to his knees before a white-haired child slowly bleeding out from a bullet wound, staining the tan stone a bright crimson which captivates him for several long moments. He blinks and moves closer, the warm breeze brushing across his shoulders in the quiet evening air, coming to a stop beside the weeping soldier. His tears trace lines down his dusty face, the dirt doing little to hide the cracks that are spreading across his mind, a dam that is about to finally break and unleash its torrent on any in its way.
People are odd creatures.
Two gunshots cry out.