Free-for-all Games
From Warzone Wiki
A free-for-all game, or a FFA, is a game where every player plays for himself, versus everyone else; however, temporary alliances might be allowed.
They usually require different strategy than duels - it is often beneficient not to immediately attack everyone you meet, and sometimes staying put for a few turns and building up armies is the best course of action. See basic strategy for FFA games.