Kanohi

"You must not remove your masks, unless you are replacing one with another. Without them, your strength is halved."

- Toa Helryx, BIONICLE Legends 10: Swamp of Secrets

Kanohi were masks worn by various bio-mechanical species in the Matoran Universe. Coming in many shapes and sizes, they were forged using either molten Protodermis, or Kanoka discs, and would often be imbued with an ability that empowered the wearer. Matoran and Turaga could fall into a coma (And possibly die shortly afterwards) if their masks were kept off for too long, while Toa and other powerful beings would be severely weakened if their Kanohi were removed; the Makuta in particular relied on their Kanohi to contain their Antidermis. The natural color for most Kanohi was a dull silver-grey; though when worn, they would change color to match the armor of their wearers. This did not apply to legendary masks or those of unique power, such as the Avohkii, the Great Mask of Light.

Powerless Kanohi
Powerless Kanohi were basic masks, with no powers whatsoever. Matoran had to wear these constantly, or else they would slowly get weaker and eventually go into a coma-like state. These type of Kanohi were forged from Kanoka discs with a power level of 6 or lower, as the power was siphoned off in the forging process. On Metru Nui, powerless masks were denoted by silver streaks painted on their top halves; on Mata Nui, these marks eventually faded away under the sun.

Noble Kanohi
Noble Kanohi were masks that contained powers, although they were less powerful than their Great counterparts. These were most commonly worn by Turaga, though their powers could also be used by a Toa. They were forged from Level 7 Kanoka disks, but could also be created when a Toa became a Turaga, being derived from the Toa's original Kanohi. Noble masks that had been forged were denoted by having the top half painted black.

Great Kanohi
Great Kanohi were masks with powers at a stronger level than Noble Kanohi. They were the most commonly seen type, after powerless masks, and were worn almost exclusively by Toa, but other powerful beings, such as the Makuta and Order of Mata Nui members also wore them. They could be forged from level 8 Kanoka disks. They could also be created when a Matoran became a Toa, their powerless mask becoming a Great Kanohi.

Toa Kaita Kanohi
Powerful and unique, the Kanohi of a Toa Kaita combined the powers of their individual Toa's merged masks. So far, only three of these so-called "Kanohi Kaita" have been formed, the Aki, the Rua and the Rua Nuva. The Aki allows for simultaneous or separate usage over the powers of shielding, strength and speed, while the Rua allows the same for the powers of levitation, x-ray vision and water-breathing.

This correlates with the Aki Nuva and the Rua Nuva, allowing for the use and sharing of the enhanced powers of the Kanohi Nuva, detailed below. The Aki Nuva was never formed however, and after Tahu was devolved back into a Toa Mata, the forming of the Aki Nuva became impossible. Lastly, the powers of these special Kanohi could only be activated by a Toa Kaita, and would only exist apart from it's wearer so long as the Kaita merging remained active.

Kanohi Nuva
Kanohi Nuva were a special type collected and worn by the Toa Nuva exclusively. They possessed even greater powers than ordinary Great Kanohi, and could even allow its wearer to share its powers with others if they were within close proximity, however these masks could only be activated by the Toa Nuva. To date, only six types of Kanohi Nuva have ever existed. The Hau Nuva, Kakama Nuva, Akaku Nuva, Miru Nuva, Kaukau Nuva, and the Pakari Nuva.

Organic Kanohi
Organic Kanohi were unique masks formed by the energy of the Red Star, and were worn only by the Toa Inika. The greatest distinction between normal Kanohi and the Inika's masks, was the organic connection between the Kanohi and their wearers. This connection allowed the Inika to learn about, and activate their mask's powers much quicker than normal, as the Kanohi themselves seemed to guide their hosts. Only six organic Kanohi ever existed, but after the Inika were transformed by the Kanohi Ignika into the Toa Mahri, these masks ceased to be. They were organic variants of the Calix, Iden, Suletu, Kadin, Sanok and Elda.

Legendary Kanohi
Legendary Kanohi were immensely powerful masks, sought after by many beings. The Kanohi Ignika, the unofficially named Mask of Creation, and the Kanohi Vahi, were the only three known Legendary Kanohi in existence. They were created by different means, with the Vahi having been forged by Vakama from the Great Disks, while both the Ignika and the Mask of Creation were made by the Great Beings. These masks were so powerful that if they were damaged within the Matoran Universe, their legendary powers would begin to bleed out into their surroundings, and if destroyed, would wipe out all traces of their effects of Life, Time and Creation.