As a Games Master, I wouldn't allow Torturer to be either a Lore, Craft or Art. And even as a Craft, it would not be made available to player characters. Too many ethical issues, and there'd always be the one player who gets bored and stupid, and wants to try it out on random NPCs and the other player characters, like the player of a thief character who suddenly says "I backstab the team leader!" out of the blue when he thinks the focus of attention's shifted away from him for a moment.
"Oh, I love it when they ask me to corrupt them." -- Me