Sithis' Touch is a light, medium or heavy armor set. When you use the Blade of Woe, you gain Major Berserk for 20 seconds, increasing your damage done by 25%.
Sithis' Touch is part of the Dark Brotherhood DLC and drops in the Gold Coast in the Overland content. You can also find it on Guild Traders. Each set item is bound on equip. You can acquire light, medium or heavy armor, jewelry and weapons for this set in the Dark Brotherhood motif style.