There are four capital cities for each faction and one neutral city.

Horde cities include:

Thunder Bluff in Mulgore
Orgrimmar in Durotar
Undercity in the Tirisfal Glades
Silvermoon City in Eversong Woods; added after the release of The Burning Crusade
Alliance cities include:

Stormwind in Elwynn Forest
Ironforge in Dun Morogh
Darnassus in Teldrassil
Exodar in Azuremyst Isle; added after the release of The Burning Crusade
Neutral cities include:

Shattrath City in Terrokkar Forest, added in The Burning Crusade

There are two types of characters in the game: Player Characters (PC) and Non-Player Characters (NPCs). A Player Character is a player’s avatar in the world of Azeroth. The color of a PC’s name tag can vary from white, green, yellow or red depending on faction and Player vs. Player (PvP) status. Non-Player Characters are AI-controlled characters that can only interact with PCs through scripted events or artificial intelligence (AI).

There are three types of NPCs. Friendly NPCs, whose names are displayed in green, cannot attack friendly characters and vice versa. Hostile NPCs, whose names are in red, are either of the opposing faction or are mobs (enemies controlled by AI) and will freely attack any PC with whom they are hostile. Neutral NPCs, whose names are displayed in yellow, are neutral and will only attack if provoked.

Some NPC interaction is affected by the reputation a PC has with them. For example, certain NPC merchants will have more items available for sale if that PC has a higher reputation with the merchant’s faction. PCs’ standing with a faction can be increased or decreased by killing certain mobs or handing in items to certain NPCs. However, PCs cannot gain reputation with opposing factions, so a Horde character cannot gain reputation with any Alliance-only faction and vice versa.

NPCs in major and minor cities can buy and sell merchandise, train class and profession skills, give quests and provide a large number of services that are needed in the game. While some will merely offer advice or further the story, others, such as city guards, patrol around set paths to keep cities defended against attacking PCs or hostile NPCs that may attempt to invade.

Main articles: Races in the Warcraft universe and Classes in World of Warcraft
Players create characters which serve as their avatars in the online world of Azeroth. When creating a character in World of Warcraft, the player can choose from ten different races and nine different character classes. The races are split into two diametrically opposed factions, the Alliance and the Horde.

The Alliance currently consists of Humans, Night Elves, Dwarves, Gnomes and Draenei (Draenei characters require The Burning Crusade expansion in order to be created.[16])
The Horde currently consists of Orcs, Tauren, Undead (specifically a faction that broke away from the Scourge called the Forsaken), Trolls and Blood Elves (Blood Elf characters require The Burning Crusade expansion in order to be created.)
In addition to the ten playable races there are many NPC races including (but not limited to) Goblins, Ogres, Murlocs, and Naga.

The nine available classes are Druid, Hunter, Mage, Paladin, Priest, Rogue, Shaman, Warlock, and Warrior. The Paladin class was previously only available to the Alliance, and the Shaman only available to the Horde. However with the release of Burning Crusade the Draenei (Alliance) are able to be Shamans and the Blood Elves (Horde) are able to be Paladins, thus removing the previous faction exclusivity. In the Wrath of the Lich King expansion, a tenth class known as the Death Knight will be added, which will also be the game’s first Hero class.[15] Classes are primarily limited by race: for example Night Elves can only be Druids, Hunters, Priests, Rogues or Warriors.

Characters in World of Warcraft are tied to specific user accounts. User accounts can be used on all servers, or realms. Characters can be moved between servers in the same region (e.g., from one European server to another, but not from a European server to an American one) for a fee. As of this time, one may move a character from a Player Versus Player (PvP) realm to another PvP realm, or a Player Versus Environment(PvE) realm, but one may not move a character from a PvE realm to a PvP realm. The two playable factions currently in the game are the Alliance and Horde both consisting of five different races each. There are a total of 9 playable classes. The Burning Crusade expansion added one new race to each faction (the Blood Elves and the Draenei).