Matoran are the main inhabitants of Mata Nui.
Physically, Matoran are small in stature, but they are strong and very enduring at heart. They are dependent upon the wearing of their powerless Kanohi, without which they will weaken and be rendered comatose. They do not, however, have the mental discipline needed to use the power of a Great or Noble Mask. Matoran have an innate connection to an element, and can manifest the ability in a small way.
Most Matoran are inherently of good nature, but can succumb to greed and desires for personal gain. An example of this is Surina, who attempted to assassinate Akiri Hahli in order to shift the balance of power in her Koro.
Many different types of Matoran exist, each affiliated with a certain element of their universe. The Matoran have different stages of power; a few of them are predestined to become Toa, and possibly later Turaga, although they are still considered members of the Matoran species. All Matoran have innate Elemental Powers, which are fully activated upon becoming a Toa. These powers are weak, manifesting themselves in small ways.
- Ta-Matoran: Matoran of Fire, can tolerate extreme heat. Their armor and Kanohi colors include red, orange, yellow, and black.
- Ga-Matoran: Female Matoran of Water, able to hold their breath longer than other types of Matoran, as well as being adept swimmers. Their armor and Kanohi colors include various shades of blue.
- Le-Matoran: The Le-Matoran are the Matoran of Air, and have great agility and speed in tall structures but are clumsy and awkward on solid ground. Their armor and Kanohi colors include green, lime-green and teal.
- Po-Matoran: Po-Matoran, the Matoran of Stone, are physically stronger than other types of Matoran. Their armor and Kanohi colors include brown, yellow, orange, tan, and black.
- Onu-Matoran: Onu-Matoran are the Matoran of Earth, and have limited night vision. Their armor and Kanohi colors include black, gray, tan, orange, and purple.
- Ko-Matoran: Ko-Matoran are the Matoran of Ice, and can tolerate intense cold. Their armor and Kanohi colors include white, gray, silver, black, blue, and sand blue.
- Vo-Matoran: Vo-Matoran are the Matoran of Lightning. They are one of the few female races of Matoran, and have a resistance to electric shocks. Their armor and Kanohi colors are blue and white.
- Fa-Matoran: Fa-Matoran are Matoran of Magnetism, and have an internal compass and a better sense of direction than other Matoran. Their armor and Kanohi colors are gunmetal gray and black.
- Su-Matoran: Su-Matoran are the Matoran of Plasma, and their eyes have protection against bright light. Their armor and Kanohi colors are orange and white.
- Ba-Matoran: Ba-Matoran are the Matoran of Gravity, and have a resistance to high gravitational pressure. Their armor and Kanohi colors are purple and black.
- De-Matoran: De-Matoran are Matoran of Sonics, and have very acute hearing. Their armor and Kanohi colors are grey and black.
- Bo-Matoran: Bo-Matoran are Matoran of the Green and have an innate understanding of plant attributes, such as poison. They prefer to live in forests or jungles and their armor and Kanohi colors are blue and green.
- Fe-Matoran: Fe-Matoran are the Matoran of Iron. They are known to be more physically endurant than other types of Matoran. Their armor and Kanohi colors are gray, metallic gray, gold, bronze, and burnt orange and vary by region.
- Cy-Matoran: Cy-Matoran are the Matoran of Crystal.
Most Matoran hail and follow the Great Spirit Mata Nui, and keep faith in his legends. They show their loyalty through their devotion to the Three Virtues laid down by Mata Nui, as well as hosting distinctive events dedicated to the Great Spirit and the virtues, and through special chants. Matoran usually have a good relationship with the Toa, and look up to the heroes as their protectors, relying on them for defense. When Toa are not present, Matoran are capable of defending themselves, organizing themselves into Militaries and fighting groups.
Formerly the Matoran were led by the Turaga, wise elders. However, the Turaga were killed by servants of the Makuta, leaving a power vacuum on the island. The Matoran elected an Akiri for each village to continue in the role of the Turaga. The Akiri are respected for their past experience with helping the Turaga and their villages.