A server in the MMORPG Asheron's Call, by Turbine and Microsoft. Darktide was launched along with the game in November 1999, and has been online ever since.
Darktide is PvP only - without safe zones or any other ability to be immune to the attacks of other players. It is generally considered to be one of the harshest environments in gaming.
The early history of Darktide is largely unrecorded, except in the memories of some of the players. Two good accounts of the epic wars and politics are "A History of Darktide" by Schattenkind and "The Call" by Aytalya