Kanohi

"Kanohi are the masks that the inhabitants of Mata Nui wear. Each one has an ability: shielding, invisibility, sonar, et cetera."

- Blade to Xeno

Kanohi, also known as Masks of Power, were mask-shaped devices that were worn by most biomechanical species native to the Matoran Universe.

Overview
Kanohi were wearable devices that were molded from protodermis into mask-like shapes that were magnetically attached to the faces of their wearers. Most Kanohi that were imbued with powers in the creation process contained powers that their wearers could activate through concentration, provided that they were a member of species that had the mental capacity to access that power. For example, powerful Matoran Universe species such as Toa and Makuta could access the powers stored in Great Kanohi masks, but Matoran could not because they lacked the mental fortitude necessary to activate Kanohi powers. However, it was necessary for Matoran, Toa, and Turaga to Kanohi masks because they became weakened if they did not: Toa felt weak and dizziness, Turaga suffered extreme weakness, and Matoran lapsed into a coma-like state if their absent Kanohi was not replaced after an extended period of time. Other Matoran Universe species that could wear Kanohi, such as the Makuta species, could wear and activate the powers of Kanohi and remove them without suffering any negative effects. For example, Makuta Blackout claimed to have never worn a Kanohi because he considered them beneath him, but the Makuta Anima wore Kanohi and often used the powers that they provided in their day-to-day lives. Organic and artificial species that were not designed to operate in Great Spirit Robots could not naturally interface with or activate the powers of Kanohi masks.

The facial expressions of Kanohi wearers could still mostly be read when they were wearing their masks because the shape of the Kanohi shifted to match their current expression. Kanohi mouthplates would also move in conjunction with their bearers' lips while they were talking.

If worn for extended periods of time, Kanohi had a tendency to retain an imprint of their owner's consciousness and identity within themselves for a short time after being removed. For this reason, a deceased Kanohi wearer could be resurrected if their Kanohi was then infused with great amounts of life force energy and placed back on the face of the deceased wearer.

Creation Process
There were several different ways to create Kanohi. The first Kanohi were created directly by the Great Beings during the construction of the Matoran Universe when they first designed the Matoran. Later Kanohi were molded by the Matoran Universe's residents, who later discovered a way to create Kanohi from Kanoka disks. On Metru Nui, Kanohi masks were made by mask makers in Ta-Metru, who would melt down Kanoka disks and reforge or carve them into Kanohi. The type of Kanoka and its power level determined what kind of mask was created and different types of Kanoka could be combined to create different masks. Level 1-6 Kanoka were formed into Matoran masks, Level 7 were turned into Noble, and Level 8 became Great. This was because power leaks from the Kanoka during Kanohi creation, so only masks made from higher level Kanoka can retain powers. In addition, if powered Kanohi are cracked or broken, they may not function properly or at all. Kanohi masks that have the same power are usually molded into the same shape due to the need to quickly and easily discern what power it has, but Kanohi can be molded into almost any shape and retain the same power as long as the material is not damaged in any way. Some Kanohi wearers, such as Bulwark, have their Kanohi remolded to resemble the Kanohi of ancient heroes to honor them.

When Great or Noble Kanohi were first created, they retained the grayish color of the protodermis that they were molded from until they were attached to their wearer, at which point the mask adopted a color that fit with the colors of the wearer's armor. Powerless Kanohi did not have this capability, so their wearers often painted them to change their colors. Great or Noble Kanohi lost their colors if they were separated from their wearer or if their power was drained by any means.

Completed Kanohi could be modified with attachments such as the telescopic eyepiece commonly added to the Akaku. These additions could also later be removed without damaging the mask if handled carefully.

Power Levels
There were five known power levels of Kanohi. From least powerful to most powerful, these were Powerless, Noble, Great, Nuva, and Legendary.

Powerless Masks
Powerless Kanohi (also known as "Matoran Kanohi") were the Kanohi that were most often worn by Matoran. These masks were specifically created without powers, but could become Great masks if they came into contact with Toa Energy, and transformed again into Noble masks when this Toa Energy was expended. This happened whenever a Matoran transformed into a Toa and again if this Toa became a Turaga after sacrificing their Toa Energy and fulfilling their predetermined destiny. Powerless Kanohi did not have unique designs; instead, all powerless Kanohi were forged in the shape of Noble or Great masks.

Noble Masks
Noble Kanohi were former Great masks that had been transformed into less powerful versions when their Toa bearer had surrendered their Toa Energy and turned into a Turaga. Though Noble masks were most often worn by Turaga, Toa could also access their powers.

Great Masks
Great Kanohi were the Kanohi worn by Toa and beings whose power level was at least equivalent to theirs, such as Makuta. Great masks contained a myriad of abilities and could only be activated by Toa or their equivalents in power.

Nuva Masks
On rare occasions, Great masks that came into contact with Energized Protodermis were transformed into Kanohi Nuva, which were masks that contained the same power, with the exception that that power was able to be shared with beings of the bearer's choice when activated. The only known Nuva masks in existence were owned by the Toa Nuva.

Legendary Masks
Legendary Kanohi were unique and extraordinarily powerful masks that were each designed to control a fundamental force of the Matoran Universe, such as Time or Life. Due to their immense power, Legendary Kanohi could not be controlled for more than a few moments unless the bearer had immense mental discipline and resolve. In addition, Legendary Kanohi could not be transformed into Noble Kanohi because it was impossible for them to exist at lower power levels.

History
Eons ago, Washu Hakubi created the concepts that inspired the Great Beings to create the first Kanohi masks and Kanoka disks.

On Metru Nui, Kanohi masks were made by mask makers in Ta-Metru, who would melt down Kanoka disks and reforge or carve them into Kanohi. The type of Kanoka and its power level determined what kind of mask was created and different types of Kanoka could be combined to create different masks. Level 1-6 Kanoka were formed into Matoran masks, Level 7 were turned into Noble, and Level 8 became Great. Production of Kanohi on Metru Nui came to a halt in 100,080 CMT when Blackout used persuasion particles to convince the Matoran to disassemble every building on Metru Nui and use the materials to build Darkmount, a replica of Atlantis, that would enable them to survive the death of Mata Nui.

Many Kanohi survived the abandonment of the Matoran Universe and continued to be used by Matoran, Toa, Turaga, and Makuta over 50,000 years later. The Reformed Second Brotherhood of Makuta even continued to create Kanohi in their foundry on Fareste.