Factions are groups of people with shared goals which they can choose to support, ignore or even outright oppose.  There are four factions in Storm of Wars: Air, Earth, Water and Fire. All factions are created equal.

Each faction owns a Citadel which is your faction's last line of defense. Protect it at all costs! If a faction is defeated, all players in that faction must choose between either surrendering to the invading faction or joining one of the other surviving factions.

The Faction Border is charged with arcane power and prevents enemy factions from teleporting their cities into your faction's homeland. Be aware, however, that it doesn't stop their armies from crossing!

It also protects the Citadel and Fortresses in your homeland from being attacked by enemy factions. To push back an enemy faction's border, a faction must capture all adjacent Fortresses outside the border and hold them through contested period. 

Once all enemy factions are defeated, the war is over and an Empire is born! The united land will be showered with Treasures and a rule will rise to lead the people in battle against rival Empires.