Matoran are one of several species immigrated from the giant robot during the Osea crisis, who have now become residents on the colony.
The Matoran were created thousands of years ago by the Great Beings, designed after the native Agori on Spherus Magna, known today as Osea. Their original purpose was to help build, and later maintain, the Great Spirit Robot. They unknowingly created this robot and the universe inside of it, not realizing they were making the place that would become their home. Upon completion, they inhabited the Robot and maintained it, working all kinds of labor to keep it running.
The Matoran were not designed to have personalities and individuality, merely conceived as maintainers for the Great Robot. However, due to intervention by an unknown source, they developed complex mental processes that manifested as personalities and individuality.
The Matoran worked, not knowing their universe was actually a massive Robot, not knowing that halting their work would jeopardize the robot and in turn their universe, and not knowing of their origins. To them, they always lived here, laboring and playing and being protected by their guardians, the Toa.
Eventually, the Matoran were enslaved by Teridax, who replaced Mata Nui as the personality of the Robot and essentially usurped his Godhood over them. Mata Nui had been cast out of the Robot, where he eventually arrived at the Skyverse and took on the title of Babylon.
After the Osea conflict, Teridax was killed but the Great Robot damaged beyond repair. The Matoran, alongside all the other species inside the Robot, migrated to the reformed Osea where they integrated with the native Agori and Glatorian, as well as the races of the UCR as part of Babylon's final wish for them all.
Matoran stand at about 5 ft tall and come in a variety of colors and a few different builds. The Matoran are Bio-mechanical, being an integration of organic and robotic parts. They were originally designed after the Agori species native to Ancient Osea, and were built as workers to maintain the Great Robot, which they were comparitavely "nano-sized" to.
They are dependent upon the wearing of their powerless Kanohi, without which they will weaken and be rendered comatose after a prolonged period of time. They do not, however, have the mental discipline needed to use the power of a Great or Noble Mask.
Matoran sustain themselves by coming into physical contact with an energy-bearing object such as a fruit, berry, or fish; they consider chewing and ingesting food as repulsive. In place of an organic heart, Matoran have some sort of power plant containing their life force. Matoran breathe oxygen and, like organic beings, they need to drink water in order to survive. They do not need to eat or sleep as much as most organics, due to their partially mechanical nature. Matoran will not undergo physical aging as long as their mechanical components are maintained, although it is unknown if they can show signs of mental aging.
Matoran are slightly physically stronger and faster than humans due to their mechanical nature; however, any enhanced can easily overpower them, with few exceptions.
There are 16 sub-types of Matoran, each identified by a different color and containing a potential elemental power; this power, while not accessible to them, manifests as traits that they possess, such as an affinity or resistance to their element.
A select number of them are also granted a special untapped power, and destined for greatness; these select Matoran, when exposed to Toa power contained within a Toa stone, are transformed into Toa and gain full access to elemental and mask powers. After completing their Destiny and expending their Toa Power, they then transform into a Turaga, where they have limited access to elemental and mask powers.
Most Matoran are inherently inclined toward being good-natured, but can succumb to greed and desires for personal gain.
Matoran are capable of fusing together into more powerful combinations by concentrating on uniting and temporarily sacrificing their individuality. The fusion does not gain any access to elemental powers, but does increase the physical abilities of the matoran being fused and possesses whatever elemental resistances of the combined matoran. The fusion gains its own personality made by the combined personalities of each matoran, unique to the combination. The matoran are able to split back to their original forms without suffering any backlash save for drained mental energy due to the concentration required to maintain the fusion.
- Ta-Matoran - Matoran of Fire, identified by main color of Red, and secondaries of Orange, Black or Yellow. Very determined and bold, sometimes to the point of arrogance and some have a hot temper. They manifest the resistance to extreme heat, though there is a limit to how much they can tolerate.
- Ga-Matoran - Matoran of Water, identified by shades of Blue. Tranquil and peaceful, they show a subconscious connection to nature. They manifest an increased lung capacity and are adept swimmers.
- Le-Matoran - Matoran of Air, identified by shades of Green. Unique in their use of "treespeak", also known as "Chutespeak", which involves strange vocabulary that often confuses others. They appear to be playful and a little lazy. They manifest increased Agility as well as clumsiness on solid ground.
- Onu-Matoran - Matoran of Earth, identified by main color of Black, and secondaries of Grey, Purple, White or Orange. These Matoran are patient and calm, but can also be stubborn. They manifest increased Strength and possess Night vision, which makes them uncomfortable in areas with bright light.
- Po-Matoran - Matoran of Stone/Rock, unique in their identification of multiple colors of Brown, Tan, Yellow, Grey, Orange or Black; their primaries depend on which region in the Great Robot they came from, the main type being colored Brown and Tan. Hard workers that are very friendly, some are also stubborn and self-centered.
- Ko-Matoran - Matoran of Ice, identified by main color of White, and secondary grey, white or sand blue. Intelligent and calculating, they can come off as cold and isolated at first, finding it more comfortable to be alone. They manifest resistance to extreme cold.
- Vo-Matoran - Matoran of Lightning/Electricity, identified by main color of Blue, and secondary White. Energetic and inclined to completing tasks quickly, they may seem a bit fast for people to get used to. They manifest resistance to electrical shocks.
- Fa-Matoran - Matoran of Magnetism, identified by main color of Black, secondary gunmetal grey. Always focused and seemingly single-minded towards their tasks, some also display a connection to nature. They are rare. They manifest an internal compass that gives them a better sense of direction.
- Bo-Matoran - Matoran of Plantlife, identified by main color of Green, secondary blue. The most connected to nature of all the Matoran, they can be seen speaking to flora as if they were sentient, and are highly adept at using what nature gives them. They manifest a better understanding of things plantlike in nature, such as poisons, of which they also have resistance to.
- Ba-Matoran - Matoran of Gravity, identified by primary color Purple, secondary black. Ba-Matoran are usually not outgoing, preferring to stay in places they are accustomed to, but won't Refuse company from visitors. They are slightly rare. They manifest resistance to gravitational pressure, to the point they can be below ground or water beyond that of which other matoran cannot go.
- Su-Matoran - Matoran of Plasma, identified by primary color Orange, secondary white. Su-Matoran do not like dark places due to their traits, and are inclined towards pieces of advanced technology. They manifest a greater resistance to heat than a Ta-Matoran and are able to see in bright light, which makes them less able to see in the dark.
- De-Matoran - Matoran of Sonics/Sound, identified by primary color grey, secondary black. They dislike excess noise, and avoid any areas where loud sound might be present, and do not speak more than absolutely necessary. They are slightly rare. They manifest increased hearing which is highly sensitive.
- Fe-Matoran - Matoran of Iron/Metal, identified by primary color gunmetal grey, secondary shades of orange. Fe-Matoran are inclined towards metalwork due to their element, and last longer on the job than anyone else due to their affinity. They are rare. They manifest increased endurance.
- Ce-Matoran - Matoran of Psionics, identified by primary color blue, secondary yellow or gold. They are highly intelligent and wary of others, seemingly able to peer into one's mind despite being unable to read mental thoughts at their power level. They manifest mental shielding that helps them resist mental intrusion and mind powers such as telepathy, telekinesis, or mind control.
- Av-Matoran - Matoran of Light, identified by primary color white, secondary yellow or gold; however, due to their chameleonic ability they can change their appearance and sport any color they choose. The most morally good-natured of all Matoran, they very rarely can be persuaded to dark deeds due to possessing full light in their hearts. They manifest more of their element than most Matoran due to them having 100% light, allowing them to project small blasts of light and change the color of their bodies.
- Kra-Matoran - Matoran of Shadow, identified by primary color black, secondary red; this applies to natural shadow matoran, whereas converted matoran sport their natural element's primary color as their shadow secondary color. Not a natural manifestation of Matoran, Shadow Matoran can be created from any element, including light, by draining them of their moral light and replacing it with darkness. The process requires 100% light to be drained to be considered a shadow matoran. A barrier is then automatically errected to keep any light from returning, which can be disrupted and destroyed by a specific frequency of sound. It is rumored Natural Matoran of Shadow are starting to appear. They manifest more control of their element than most matoran, being able to fire small blasts of shadow.
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. However, most other beings can easily overpower them, thus they mostly rely on the protection of Toa.
Since they essentially worship Mata Nui as their God, the Matoran find it difficult to intigrate with the UCR despite their good nature; their morals conflict with the beliefs in the Gods and Goddesses of the Skyverse. Babylon recognized this and as part of his last wish, tried to persuade his UCR allies to work with the Matoran and come up with a way that they could follow their virtues and still live with the UCR in peace.