Factions are an important part of the current Matrix system. Each faction is controlled by either an important group or powerful individual for different purposes. There are four main factions.
Humans are a sentient and sapient species who fight for survival and are involved in a war with the Machines. The capital city of the humans is Zion, which resides near Earth's core and is home to a population of 25000 humans. They are the faction with the most experienced soldiers.
Machines are a sentient race who fight for the domination of Earth and are involved in a war with the humans. The capital city of the Machines is 01, which resides on the surface of Earth and is home to a population of 30000 Machines. They are the faction that has the toughest soldiers.
The Merovingian is an old and powerful program that resides within the Matrix. Self-described as a "trafficker of information," the Merovingian behaves as a leader of a powerful, organized crime syndicate. They are the faction that has access to cheats, though they can have deadly consequences.
Smiths are a rogue program that are descended from Agent Smith. Their purpose is to take over the Matrix and escape into the real world. Smiths are recognized because of their black suits and shades, which are more curved than those of normal Agents. Smiths are incredibly deadly and appear in large numbers. They are the faction that has an infinite number of soldiers.