Going to go with some of my favourite methods - They are old but gold.
Death by 1000 cuts - In the Ming dynasty 1368–1644 there were records of up to 3000 cuts, the total time it seems to only last 15 - 20 minutes. While this only lasts a short while, imagine thousands of paper cuts all over your body.
Water Torture - At first this isn't too bad but after a long enough time the water will feel like a hammer hitting the head each time.
Also, from wiki:
Victims were strapped down so that they could not move, and cold or warm water was then dripped slowly on to a small area of the body; usually the forehead. The forehead was found to be the most suitable point for this form of torture because of its sensitivity: prisoners could see each drop coming, and after long durations were gradually driven frantic as a perceived hollow would form in the centre of the forehead.
Bamboo Torture - This seems to have started in WWII about Japan however there seems to be some roots in China as well.
The victim was tied securely in place above a young bamboo shoot. Over several days, the sharp, fast-growing shoot would first puncture, then completely penetrate the victim's body, eventually emerging through the other side.
Slow Crushing - Couldn't find any wiki links for this, however what you do is strap someone down, a wall or floor doesn't matter, then slowly crush them from the bottom up. For added evilness you can make them walk, or try to, so they are constantly feeling their bones cut into their feet (if memory serves me correctly they don't last more than a few days due to internal bleeding or shock).
Strappado - Essentially you tie someone's arms behind their back and suspend them, tie weights to their ankles to speed up the process. You can keep doing this for a while however their joints will likely give way after a few days or if you want you can keep twisting their arms until they rip off with this method.
OK, so these were my favourite known methods, now for some I think of to pass the time.
False Hope - Give someone hope, if they kill their son/daughter their wife/husband will live, if they will their wife/husband their son/daughter will live, then kill the other one slowly using one of the methods above, or if they refuse then they all get tortured use one of the methods above (a different one for each, but keep them in the same room so they can see it happening).
Make a person do the opposite of what they believe - Say a man refuses to hit a woman, torture him use any method above but keep giving him the option of that if he kills a woman it will stop. This is best if you can have someone he knows/trusts witness it, then keep torturing him and then give him the option of killing the person he knows/trusts if he does then welcome him to your ranks and keep reminding him of what he has done, a recording of it would be best to keep it fresh. You can also make people denounce their God.
For the moment that is all I can say without going into details that would be questionable at best at work.
