There are five (six in Warband) main factions in Mount&Blade. They are constantly at war, trying to take over each others' territory and fiefs. But they will never conquer a whole faction without the help of the player.
A faction will be eliminated a few days after all of their territory has been conquered and all of their armies have been defeated. If a faction has had all of its territory conquered, but then regains a fief, the time until elimination will be reset, and the vassals of that faction will be able to start recruiting again.
Each faction is distinguished by a different style of army: some have excellent infantry, others excellent archers or cavalry, or a combination of these.
Each faction has a monarch and his vassals, as well as a claimant to the throne who waits for someone (the player) to champion their cause. The claimants can be found in random town keeps, and you can ask a traveller for their location for 30 denars. Claimants will never be found in a town belonging to the faction for which they are the claimant. For example, Prince Valdym the Bastard will never be found in a keep belonging to Kingdom of Vaegirs.
The player can join a faction, start a rebellion, or create their own faction. In the original Mount&Blade, a player who has created a faction cannot have lords at their service. They are regarded as a rebel faction, and the player as sole Lord is forced to protect and expand the entire kingdom. This is not the case in Warband; a player may assign companions as vassals and convince rival lords to defect.
The factions present at the start of the game are listed below. For more information on each, go to their respective pages.
|Khergit Khanate||Sanjar Khan||Dustum Khan||Purple||South|
|Kingdom of Nords||King Ragnar||Lethwin Far-Seeker||Yellow||North|
|Kingdom of Rhodoks||King Graveth||Lord Kastor of Veluca||Cyan||West|
|Kingdom of Swadia||King Harlaus||Lady Isolla of Suno||Orange||Central|
|Kingdom of Vaegirs||King Yaroglek||Prince Valdym the Bastard||Green||East|
|Khergit Khanate||Sanjar Khan||Dustum Khan||Purple||East-Central|
|Kingdom of Nords||King Ragnar||Lethwin Far-Seeker||Cyan||Northwest|
|Kingdom of Rhodoks||King Graveth||Lord Kastor of Veluca||Green||Southwest|
|Kingdom of Swadia||King Harlaus||Lady Isolla of Suno||Orange||West-Central|
|Kingdom of Vaegirs||King Yaroglek||Prince Valdym the Bastard||Gray||Northeast|
|Sarranid Sultanate||Sultan Hakim||Arwa the Pearled One||Yellow||South|