The Dremora Mace, as with all Dremora weapons and armor pieces, bears a striking resemblance to the Daedric Mace. These two are not to be confused, as the Dremora equipment does indeed have the same weight level, but is significantly less expensive. It also has a much lower attack rating, and is much more common to find at lower levels than the other weapons.
These are always carried by Dremora enemies, which are found in or around the planes of Oblivion at lower levels. Dremora Churl always carry these weapons with them, and will spawn immediately with one at level one.