An altar and place of worship is usually on the ground floor and/or basement, which is why abandoned churches are frequently chosen as their bases of operations or one of the buildings on cult controlled grounds. Many churches have a second small altar and gathering place in their basement, back room, or the neighboring rectory.
These often conduct rituals to draw the power from the victims of war and send them into a dimensional vortex, where they are absorbed by the God-King to utilize that power in the Transcenion.