The Martense Order (also known as the Martense Coven) was an order of all female witches who fought against the Great Old Ones. They are the sworn enemies of the Black Brotherhood, and its leader ZZ Ziltch. Celeste, one of the heroes exploring Lorwich, was a member.
In 1752, the Vatican worked with, unofficially with the Martense order to combat evil. 
The coven was led by a Queen.
Despite having worked together with the Vatican to a greater extent than the Black Brotherhood, it is speculated that the relationship between the two groups are not perfect. This is evident when hearing the except quote of Aurora "that the bible can be destroyed by wind and rain, the Martense order IS the rain and wind."
- Queen/High Priestess
- First Sphere
- Second order
- Third Sphere
The magic used by the witch's coven relied on the source of light or illumination to replenish their energies.
- Martense was a reference of a family line in The Lurking Horror.
- ↑ Hallowed Catacombs- Priest transcript