Krana

"Beware the krana! When worn, they can steal the mind...and not even a Toa might be able to resist their power."

- Turaga Vakama, Comic 4: The Bohrok Awake

Krana were a type of organic species which acted as the brain of a Bohrok and gave it its power. The Krana, besides controlling the Bohrok, provided intelligence to the swarms.

History
Krana were first created by the Great Beings as part of creating the Matoran Universe. Later generation of krana were created and telepathically guided by Cahdok and Gahdok, the twin queens of the Bohrok swarms. If the queens were either not awake or had their connection severed, the krana, and therefore the Bohrok, would not be able to operate to their fullest performance. A small amount of krana were exposed to a mutagenic substance, which altered them into enhanced forms known as Krana-Kal.

The krana--while the Bohrok's source of power--was also its weakness. Even the strongest Bohrok without its krana became little more than an empty shell, which could then be programmed or trained to repair the damage it inflicted. One of the main functions of the Bohrok Va scouts was to replace a Bohrok's missing krana. If one felt threatened, it could eject from its Bohrok host; this left the host powerless, but if the krana attached onto another being's face, it took control of that being's mind and assimilated it into the swarm.

Krana were known to the Matoran on Metru Nui, and specimens of them were preserved in the Onu-Metru Archives. At one point, Toa Metru Whenua almost stumbled into a display case containing krana and was greatly relieved he had not accidentally released them.

After the Toa Mata defeated Makuta, he prematurely awoke the Bahrag, who promptly unleashed the Bohrok swarms upon the island of Mata Nui. During this time, almost the entire population of Le-Koro were exposed to the mind-altering powers of the krana, before they were later freed. The six Toa collected forty-eight krana--eight from each Bohrok breed--and placed them into special slots in the middle of their underground nest. This unlocked the hiding places of six Exo-Toa and the inner lair of the Bahrag. When the Bahrag were defeated, the Bohrok shut down and the Matoran collected and sealed all their krana away.

The Toa Nuva were later sent on a mission by Order of Mata Nui member Axonn to free the Bahrag, so that they could re-release the Bohrok swarms and revert Mata Nui into a barren state.

Types
There were eight different types of Krana. Each one granted their wearer a unique power and assigned them a rank in the Bohrok swarm:


 * Xa: Swarm Commander--Strategy. This krana led the Bohrok on their mission. Krana Xa command a swarm, giving their Bohrok the ability to form complex plans in order to complete their mission.
 * Za: Squad Leader--Telepathy. This krana gave their host the ability to communicate telepathically with other krana of the swarm. This type of krana controlled Lewa and Turaga Matau for a period of time.
 * Vu: Surveyor--Flight. This krana gave their host the ability to fly short distances ahead of the swarm to confirm that the path is clear, avoid obstacles, or escape a threat.
 * Ca: Clearance--Shielding. This krana gave their host the ability to generate a powerful shield for themselves and others; this type of krana spearheaded the swarm's mission.
 * Yo: Mole--Tunneling. This krana gave their host the ability to tunnel through almost anything on Mata Nui.
 * Ja: Scout--Radar. This krana gave their host radar-like senses which could detect distant obstacles in the path of the swarm. They can help make a swarm aware of possible danger or a hold-up.
 * Su: Worker--Strength. This krana gave their host colossal energy and inhabited the strongest of Bohrok. They were always around whenever brute force was needed.
 * Bo: Sentinel--Infrared. This krana gave their host the ability to see in the dark and serve as night-time lookouts, leading their Bohrok into the darkest places on Mata Nui.

Colors
Each breed of Bohrok wore a different colored Krana. The Bohrok's Krana color corresponded with their eye color:
 * Blue: Tahnok
 * Orange: Gahlok
 * Red: Lehvak
 * Green: Pahrak
 * Yellow-Green: Nuhvok
 * Light Blue: Kohrak

Dormant
The colors of the Krana, while dormant and carried by a Bohrok Va, were different:
 * Yellow: Tahnok Va
 * Purple: Gahlok Va
 * Dark Grey: Lehvak Va
 * Tan: Pahrak Va
 * Black: Nuhvok Va
 * White: Kohrak Va

Quotes
"The energies of the krana Ja alert the Tahnok to Toa lying in wait ahead. The telepathy of the krana Za spreads the news to the rest of the troop: "Alert! Obstacles! Avoid or remove.""

- Comic 5: To Trap a Tahnok

Set Information

 * A Krana was packaged at random with every Bohrok set; the probability of the Krana being a Xa, for example, was 1 of 8 for each Bohrok breed.

Trivia

 * The "Fohrok", unlike Bohrok, were not controlled by Krana.
 * The Krana would work just as well as a Kanohi on a Matoran's face to keep them awake and alive; however, it also meant that the Krana would be able to assimilate the Matoran into the swarm if the Bahrag awoke.
 * Concept art of the Rahkshi for the BIONICLE: Mask of Light movie depicts them as being controlled by Krana rather than Kraata, though these designs ultimately went unused.

Appearances

 * Comic 4: The Bohrok Awake - First appearance
 * Comic 5: To Trap a Tahnok
 * Comic 6: Into the Nest
 * Comic 7: What Lurks Below
 * Bohrok Online Animations
 * Bohrok (mini-comic)
 * Secret of the Swarm
 * Into the Nest (mini-comic)
 * BIONICLE Chronicles 2: Beware the Bohrok
 * BIONICLE Chronicles 3: Makuta's Revenge - Mentioned only
 * BIONICLE Chronicles 4: Tales of the Masks - Mentioned only
 * The Official Guide to BIONICLE
 * BIONICLE Adventures 1: Mystery of Metru Nui - In flashback
 * BIONICLE: Metru Nui - City of Legends Comic 1 - In flashback
 * BIONICLE: Metru Nui - City of Legends - Mentioned only
 * BIONICLE: Rahi Beasts - Mentioned only
 * BIONICLE: Encyclopedia
 * BIONICLE: Encyclopedia Updated
 * Comic 12.5 - Mentioned only
 * BIONICLE Legends 10: Swamp of Secrets - Mentioned only