Factions

In the legend of the Bionicle, there are several different factions in power and in greatest population. Each employ agents to do their duties. The main ones are:

Matoran
The people of the Matoran faction are the protagonists of the Bionicle. It consists of those who are "average" and loyal to Mata Nui: The Toa, Matoran, and Turaga. The overlying doctrine of Matoran society is the Three Virtues: Unity, Duty, and Destiny. The Matoran have numerous social norms, like the sport of Kolhii, and the casual forging and use of Kanohi. They predominately live in Metru Nui.

Dark Hunters
The Dark Hunters are a group of beings headed by The Shadowed One, specializing in bounty hunting, assassination, and espionage. They include creatures of various species, and will do anything if the price is right. They are neutral in quarrels that aren't their own, but have fought for and against both sides.

Brotherhood of Makuta
The antagonists of the Bionicle. The Brotherhood of Makuta is an organization of the Makuta species who were once loyal to Mata Nui. They became corrupted and cast Mata Nui into a deep sleep in the Great Cataclysm. They wielded advanced weaponry and powers, and would often mutate beings, with strange results. To spread their corruption, they employed leech-like Kraata to infect masks and other objects, which in turn would infect and control Rahi and other beings.

Order of Mata Nui
The Order of Mata Nui is a very secretive organization, only known to by few. Most are fiercely loyal to Mata Nui. They are associated with beings of great power and unknown race, and fight the Brotherhood of Makuta.

Visorak
The Visorak were a spider-like race composed of several swarms (analogous to the Bohrok, seen below) under a military dictatorship ruled by Sidorak and his lieutenant, Roodaka. Wielding rhotuka, machine weaponry, Rahi slaves, and a strange mutating poison, they took over Metru Nui under the banner of a vengeful Makuta.

Barraki
Six warlords and their armies, who had been banished to The Pit for plotting against Mata Nui. Because of the mutagen in the sunken-underwater Mahri Nui, the Barraki have mutated and taken the appearance of water Rahi. They used Squid Ammo and their fierce reputation to keep the ocean in check and menace the Matoran, while at the same time, searching for the salvation of the Mask of Life.

Bohrok
Built by an unknown race of inventors, the insectoid mechanical Bohrok had one purpose: to restore Mata Nui to its "before time" state, when it had been completely abandoned. Makuta awakened them before then, unfortunately. The Bohrok were hive-like in structure, commanded by the Bahrag, their queens. Their bodies were controlled by sentient, power-imbued parasites called Krana installed in their heads. These Krana could control other beings, as well. Bohrok also had drones and secondary workers, called Bohrok Va.

Hand of Artakha
The Hand of Artakha is a mysterious organization that does not exist anymore.