What is "xsyon"

Xsyon is a Sandbox MMORPG massively multiplayer online role-playing game developed by the independent company, Notorious Games. Xsyon is set in an apocalyptic fantasy environment, closely modeled on the real world area of Lake Tahoe Lake Tahoe which spans the California and Nevada border, west of Carson City using US Geological Survey data. Xsyon is a persistent world crafting Sandbox game. It has been designed to have a completely player-driven economy and player-created questing system. This is unusual among MMORPGs, which often rely upon Non-Player Character vendors and quest givers to perform these functions. Xsyon can be found on many sandbox MMORPG game lists. The game world is currently both Player versus Environment (PvE) and open Player versus Player (PvP), with players being safe from other players only in the starter area (Founder's Isle) and on their own tribe land.