Guild versus guild

Basics
As the name says, Guild versus Guild (GvG) matches are fought between two guild parties. Guild matches take place as one of the following:
 * Rated matches in the official guild ladder.
 * An unrated "friendly match".
 * An unrated guild scrimmage between members of the same guild and alliance or with Guild Hall Guests Privileges.
 * As part of various tournaments hosted by ArenaNet and other groups. Guild Wars Factions Championship (GWFC) and the more recent Celestial Tournament are examples of other form of matches.

Matching
When setting up you can choose to challenge a specific guild in an unrated match or set up an automatic, rated guild match. Unrated matches will not affect either guilds' rating or rank, regardless of the outcome. For automatic matches, Guild Wars will try to match similarly rated guilds against each other, but will eventually match guilds of disparate ratings if necessary. Guild matches can only be started with a party of at least four members from the guild including the guild leader or an officer and three other non-guest members. The team with the higher ranking will be designated the attacker, while the team with the lower ranking will be defending. On the rare occasions that guilds are of equal rank, the team with the higher win/loss ratio is designated as the attacker.

The playground
GvG battles take place on the Guild Islands. Each guild island features two bases and a flag stand in the center area. The guild with higher guild rating is assigned the part of attacker, thus the lower rated guild (or defending guild) plays in their own hall. On most maps the attacker has a slightly weaker position (for example, fewer NPCs or lower ground).

Depending on the type of Guild Hall there may be additional strategic features like catapults, portals, and more. Read the Guild Island Description for details.

Objectives
The objective of a GvG match is to kill the opposing team's Guild Lord, an NPC character, who is sitting in the opponent's base and has several other NPCs who guard him. If the Lord is killed, that Lord's team loses. Alternatively, if an entire team has -60% Death Penalty, that team loses. If the game lasts for 28 minutes, the team that showed the most aggression is declared the winner.

In GvG battles each guild has a flag that spawns in or near their base. Putting your guild's flag in the flag stand (usually near the island center) and holding it for more than 2 minutes will give your team a 10% morale bonus.

''Note: In a GvG match all dead players (but no NPCs) will automatically be resurrected by the Resurrection Shrine in their base every 2 minutes. (Provided their Death Penalty hasn't reached the maximum of -60%. At that point a player can only be resurrected by another party member.)''

Team setup
Each GvG team consists of eight players, including:
 * At least one officer of the sponsoring guild;
 * 3 or more additional members of that guild;
 * no more than four players who are guild guests or henchmen

Additionally, each of the teams' bases are guarded by several NPCs:
 * Archers (Ranger)
 * Footmen (Warrior)
 * Bodyguard (Elementalist)
 * Guild Lord (Warrior/Ranger)
 * Knights (Warrior)

Rewards
The winning guild members gain faction and guild rating, while the losing guild loses guild rating. The winning guild members gain more faction the higher rated their guild is. The rating changes depend on the relative ranking of the guilds involved. If a guild with a high rating defeats one with a low rating, neither guild's rating will change much. If the lower rated guild wins, however, the change will be much larger. The change for two similarly rated guilds will fall between these extremes. This is because the Guild Wars ladder rating uses an Elo rating system which means that how many kills or deaths you managed and how long you played for are not taken into account, only the overall result is.