Watch Station Oertha is a bastion under siege, situated on a semi-arid world within one of the primary warzones of the Achilus Crusade's Canis Salient. The forces of the T'au expansion effort believe the planet of Oertha possesses vast resources of fuel and primary materiel.
Oertha has been a prime candidate for exploitation and colonisation by the T'au Empire forces in the Reach for some time. The world's largely uninhabited status has led the T'au to lay claim to the planet; a claim that is disputed by the watch station and the Imperial forces within it.
Watch Station Oertha is a sprawling and heavily fortified compound that stands concealed in the maze-like ravines of the equatorial Berrick Mountains of Oertha. In a rare instance of overt and ongoing cooperation between the Achilus Crusade's forces and the Deathwatch, Watch Station Oertha has now become the keystone of the Imperial efforts to deny the planet to the T'au.
Twenty Deathwatch Battle-Brothers, under Watch Codicier Kurita, and fifty allied Astartes of the Storm Wardens Chapter have garrisoned the watch station, using it as a base from which to launch a campaign of devastating raids against the T'au.
So far, these raids have made it all but impossible for the T'au to expand on the planet. As matters stand now, both sides are awaiting reinforcements, and only time will ultimately determine the fate of Oertha.
- Deathwatch: Core Rulebook (RPG), pg. 335