Kanohi

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

- Blade explains Kanohi to Xeno

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

Overview
Kanohi are wearable devices that are molded from protodermis into mask-like shapes that are magnetically attached to the faces of their wearers. Most Kanohi that were imbued with powers in the creation process contain powers that their wearers can activate through concentration, provided that they are a member of species that has the mental capacity to access that power. For example, powerful Matoran Universe species such as Toa and Makuta can access the powers stored in Great Kanohi masks, but Matoran cannot because they lack the mental fortitude necessary to activate Kanohi powers. However, Matoran, Toa, and Turaga must all wear Kanohi masks because they become weakened if they do not: Toa feel weak and dizzy, Turaga suffer extreme weakness, and Matoran lapse into a coma-like state if their Kanohi is not replaced after an extended period of time. Other Matoran Universe species that can wear Kanohi, such as the Makuta species, can wear and activate the powers of Kanohi and remove them without suffering any negative effects. For example, Makuta Blackout has never worn a Kanohi because he considers them beneath him, but the Makuta Anima wear Kanohi and often use their powers. Organic and artificial species that were not designed to operate in the Matoran Universe cannot naturally interface with or activate the powers of Kanohi masks.

The facial expressions of Kanohi wearers can still mostly be read when they are wearing their masks because the shape of the Kanohi shifts to match their current expression.

If worn for extended periods of time, Kanohi have 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 can be resurrected if their mask is then infused with great amounts of life force energy and placed back on the face of the deceased wearer.

Creation Process
There are 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 are first created, they retain the grayish color of the protodermis that they were molded from until they are attached to their wearer, at which point the mask adopts a color that fits with the colors of the wearer's armor. Powerless Kanohi do not have this capability, so their wearers often paint them to change their colors. Great or Noble Kanohi lose their colors if they are separated from their wearer or if their power is drained by any means.

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

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

Powerless Masks
Powerless Kanohi (also known as "Matoran Kanohi") are the Kanohi that are most often worn by Matoran. These masks are specifically created without powers, but can become Great masks if they come into contact with Toa Energy, and transform again into Noble masks when this Toa Energy is expended. This happens whenever a Matoran transforms into a Toa and again if this Toa becomes a Turaga after sacrificing their Toa Energy and completing their destiny. Powerless Kanohi do not have unique designs; instead, all powerless Kanohi are forged in the shape of Noble or Great masks.

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

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

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

Legendary Masks
Legendary Kanohi are 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 cannot be controlled for more than a few moments unless the bearer has immense mental discipline and resolve. In addition, Legendary Kanohi cannot be transformed into Noble Kanohi because it is 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.