After you have familiarized yourself with the arenas, you now need to take the decision on which faction you want to join and for which beliefs to fight.
There are 5 factions to choose from, each with its own rules.
White Lotus- this is the secret order, started by Raiden, which unites all of the greatest martial artists. Their goal is to perfect their combat skills, thanks to which they will attempt for victory in the Mortal Kombat tournament.
Special Forces - this is a military faction. Its members formed a group which, using cutting-edge technologies, protect the Earthrealm from the Outworld invaders.
Brotherhood of Shadow - This faction serves the Elder God Shinnok. Their only goal is to wreak chaos among people and cause as much suffering as possible.
Black Dragon - The faction of mercenaries, who do not shrink from getting their hands dirty, even by doing the most atrocious of deeds. This faction is led by Kano.
Lin Kuei - The clan that follows the orders of Sub-Zero. Lin Kuei comprises of highly-trained assassins, whose domain is surprise attack.
Which faction you pick, affects your game. Each fight, each vitory or defeat means points for your faction. Also, each faction orders its members to perform specific tasks, such as fighting several fights with a given opponent, executing certain moves, etc. Members of factions also can use the, so called, Faction Kill finishers. It is a good idea to strive for points for your faction, because the global ranking is reset every week and the winning faction receives special rewards.