The rules for Warhammer 40,000 are written for battles fought between two players, each commanding an army. However, it is equally enjoyable to play multiplayer games between three or more players, each striving separately to defeat their opponents!
In a multiplayer battle there can be as many sides as there are players! Each player must attempt to defeat all of their opponents, using any means at their disposal in order to achieve victory. It is very simple to play a multiplayer battle, and only requires a handful of minor modifications to the core rules, which are detailed in this download.
Download these rules directly from Games Workshop here!
Read more about these rules at the Warhammer Community site here!