The Shadow Geomancy creates a complex rip in the fabric of space that ties a location in the Twilight Lands or the Light Side into the Dark Side. While within the Geomancy’s indistinct bounds a Black Order Mage casts magic as if they were on the Dark Side, and in addition gains D3 less fatigue for every spell they cast.
A Shadow Geomancy can only exist where darkness reigns. Even a sliver of unfiltered sunlight will dispel it. While it may be maintained inside a sealed and windowless chamber, it is more common to use spells such as Closing of the Eye or Crossing the Border both of which allow the Geomancy to be created. Regardless of the size of the shadow, the Geomancy only covers 10 strides square. Once cast the Geomancy slowly poisons the land around it, sucking the vitality from the soil. If the shadow that contains it has not failed first the Geomancy will break apart after a number of days equal to the Mage's Level.
The Shadow Geomancy spell also has an alternative use. Cast in combination with Greater Circle of Protection it can create an area of permenant magical protection known as a Geomantic Circle. This version of the spell requires both spells to be cast in succession, and causes the casting Mage to lose 2 points of Physical. The area created is a dead zone. Anything within it has MD +8 and also -15 to all channelling attempts. In addition spirit creatures are unable or unwilling to enter the Geomantic Circle. The presence of a Geomantic Circle is easily perceived by anyone with magical skills. Unlike a Geomancy the Geomantic Circle is permenant, although physically destroying the marked circle ends the spell.