Somnomancy is a form of Thaumaturgy connected to the creation, destruction and manipulation of shadows. It is generally considered one of the most difficult forms of thaumaturgy to master, and as a result is also considered one of the most powerful. A Somnomancer, is able to manipulate the intensity, focus and movement of shadows by force of will alone. As such, they can create dangerous shadow creatures or use an opponents own shadow as an assassin.
It is considered in opposition to Luminomancy, which is focused upon the creation, manipulation and control of light.