Matoran were a race of biomechanical beings living in the Matoran universe and were the species chiefly responsible for maintaining the colossal robotic body of Mata Nui. As such, Matoran enjoyed special status as workers considered vital to the well-being of Mata Nui, whom they revered as a deity known as the Great Spirit. Matoran lived by the Three Virtues given to them by Mata Nui: Unity, Duty, and Destiny. Matoran inhabited numerous lands throughout the Matoran universe, including Metru Nui, the southern and northern continents, and Artakha.
Matoran were relatively small in stature and designed for labor, not combat. Matoran were divided into several sub-types, or tribes, based on the elemental powers. Although Matoran of most types had no special abilities, each type had attributes that made its members better suited to live in environments associated with its element. For example, Matoran of Fire were resistant to heat, and Matoran of Water were skilled swimmers. In order to function properly, all Matoran needed to wear a Kanohi mask, which served as a long-lasting power supply. Any Matoran who spent an extended period of time without wearing a Kanohi would lapse into a condition resembling a coma. As Matoran were unable to access abilities granted by Kanohi Masks of Power, they generally wore Kanohi without powers, using them solely for life-sustaining purposes. With the exception of Av-Matoran, Matoran of a particular tribe were all of the same gender (male or female), and most Matoran tribes were male. Given Matoran's biomechanical nature, gender in Matoran was not so much a physical trait as it was a psychological one.
Matoran were the beginning of the Matoran-Toa-Turaga life cycle. A select few Matoran could, if infused with Toa power, transform into Toa, champions of justice who protected Matoran. Toa could in turn transform into Turaga, respected leaders of Matoran communities. Only Matoran who were destined to become Toa could be so transformed.
After Makuta Teridax was defeated and the Matoran universe was irreparably damaged, all Matoran migrated to the surface of Spherus Magna to build a new civilization with the native Agori and Glatorian.
The Matoran of Mata Nui lived in six villages, called koro. The villages were spread out in different regions of Mata Nui, and they were all distinct and had very different kinds of buildings as well as customs. Although the Matoran were very loyal to their native villages, all Matoran shared a common dream: to defeat Makuta and live in a land of peace and beauty.
On Mata Nui, the Matoran loved many sports, and kolhii was by far the most popular.
As of mid-story year 2004, 1,000 Matoran inhabited Metru Nui.
Matoran were villagers on Metru Nui, Mata Nui, Voya Nui, Mahri Nui, and elsewhere. There were seven known types of Matoran: Ta-Matoran, Po-Matoran, Onu-Matoran, Le-Matoran, Ko-Matoran, Ga-Matoran, and Av-Matoran. Each type was normally identified by armor and mask coloration. Matoran were the only beings shown to be able to evolve into Toa. Groups of six Matoran, one from each village, were capable of merging into a Matoran Nui.
The Matoran lived on Metru Nui until they were captured by Makuta and forced into Matoran spheres, where they were thrown into a form of suspended animation. This lasted until they were brought to Mata Nui and awakened by the Toa Metru. Over time, as an after-effect of their time in the spheres, the Matoran's bodies shrank in stature, and they lost all memory of their lives on Metru Nui.
Matoran wore Kanohi which had no extra powers. However, wearing them was essential for Matoran, as having a mask off for too long could lead to a condition resembling a coma.
Matoran were granted special status in Mata Nui's eyes.
Matoran made notoriously poor conquering armies.
On Metru Nui, the body of a murdered Ta-Matoran was once taken to a slab in Ta-Metru.
Matoran workers were always among the most important inhabitants of the Matoran universe; without them, the will of Mata Nui could not be carried out.
The Matoran living on Metru Nui had the means to have new Matoran come into being. This was not possible on the island of Mata Nui.
Tens of thousands of Matoran lived on the southern continent alone.
The actual building of the Mata Nui robot was done by nanotech wonders called Matoran, who would one day inhabit the robot and keep it functioning properly.
A Matoran's Rhotuka would not necessarily be elemental, but it would be relatively weak (weaker than a Toa's or Roodaka's).
Mata Nui only required the Matoran, not other species, in order to live.
Countless Matoran came into being since the Great Beings created Mata Nui, so naturally they did not all receive their names from the Great Beings, but came up with their own names.
Turaga were able to create Matoran as needed. For example, if there were some massive project in a city that required more workers, Turaga could produce them. Makuta also had the ability to create Matoran.
The purpose of the Matoran was to keep the parts of the Mata Nui robot's body functioning, such as Metru Nui, which served as the brain.
Before Velika tampered with the Matoran's intelligence, they were sentient, but they did not have access to any kind of emotional programming. They simply did their jobs, and were not building a culture or forging friendships.
Masks provided Matoran a largely unending power source so they could keep working.
If a Matoran lost his Kanohi for an extended period of time and slipped into a coma-like condition, simply replacing the Kanohi would wake him up again.
When new Matoran were created by the machines controlled by the Turaga, they did not come out already wearing a Kanohi, but rather were given one.
The Matoran were reduced in size during their time on Mata Nui because Makuta robbed them of their powers. Before arriving on Mata Nui, the Matoran resembled the forms they had after they eventually rebuilt themselves. They had been shrunk because Makuta had been draining their powers since they arrived on Mata Nui.[25, 26]
Matoran were not able to use mask powers, even when the mask had a power like those worn by Toa. Matoran did not have the mental discipline or knowledge needed to make Great or Noble Masks work.[28, 29]
After the Matoran on Mata Nui were rebuilt, they were still able to merge.
Av-Matoran were prototypes for the rest of the Matoran. Not knowing at that point how many Toa might be needed to manage the Matoran universe, the Great Beings made Av-Matoran with an especially high potential to become Toa. However, having such a high percentage did not make much sense, since more resources would have been needed to make more Matoran to replace them, so the percentages were cut down for subsequent tribes.