There are four factions in Orna. You may pick a faction once you reach level 10. Choosing a faction will add that faction's background and name to your character portrait across all menus. You will receive a 10-20% boost to damage done with and take reduced damage from the corresponding faction's element-type skills (Spark as Stormforce, for instance).[1]

Faction Element Specialization Class Unique Spell Background
Earthen Legion Earth Legionnaire Heal
Stormforce Lightning Storm Knight Shock
Knights of Inferno Fire Scorcher Burn
Frozenguard Water Frost Mage Freeze

There are four faction classes available, and only one is accessible based on the faction you selected. It is possible to purchase the specialization class that matches your faction for real money in the Orn Shop menu.

The developer of the game has stated there are bigger plans for factions in the future.