Guild Wars players go online to take the roles of wizards and warriors in a medieval fantasy world, where they'll battle and adventure on their own, cooperatively, or — as the title suggests — in guild warfare against teams of other players. The game world is home to a once-proud kingdom, which has recently been overrun by the forces of evil and chaos. Available player professions include warriors, rangers, monks, mesmers, elementalists, and necromancers, and players are encouraged to choose a combination of any two professions for each character they play. More options become available in a series of planned "chapter" updates to the main game.

Guild Wars features common world areas, such as towns and outposts, where all players can gather and meet, but the game is particularly mission-based. When players embark on a quest, alone or in a small party, a private area of the game world is created for them, and nearly all of the real adventuring takes place in these exclusive territories. More similar to the multiplayer structure of games like Diablo or Dungeon Siege than conventional "massively multiplayer online role-playing games" (or "MMORPGs"), the developers refer to Guild Wars as a "competitive online role-playing game" (or "CORPG").

With its North American operations led by Ultima Online creator Richard Garriott, South Korean publisher NCSoft has been a principal figure in the realm of persistent world gaming, releasing three games — Linage II, City of Heroes, and Guild Wars — between spring 2004 and spring 2005. Guild Wars uses a different method for ongoing customer payments than most MMORPGs, however. Players log into the game through the developer's "ArenaNet" service, which works similarly to Blizzard's "Battle.net." The Seattle-based ArenaNet development studio was founded by former member of the Blizzard team.

Instead of requiring a monthly subscription fee, the Guild Wars plan is to release regular expansion "chapters," which advance the game world story but can only be accessed by players who pay for them. While Guild Wars players will have to purchase each new chapter they choose to use, they won't be charged any recurring subscription fees to play the basic version of the game for as long as they'd like, and participating in new chapters is always optional. ~ T.J. Deci, All Game Guide