Kaj

Kaj is an Onu-MatoranOnu-MatoranEarth-wielding Matoran of the deep who adapted to darkness and built the Matoran Universe's defensive cavalry. of EarthEarthEarth is one of the elemental powers of the original BIONICLE story, wielded by Toa such as Onua and Whenua and felt by Onu-Matoran as sharp night vision.. Little is known of his life on Metru NuiMetru NuiThe city beneath Mata Nui functions as the Great Spirit's brain, housing the Matoran whose labor keeps the god alive., though he may have served as an Archives guard alongside Damek.

On Mata Nui, Kaj was a citizen of Onu-KoroOnu-KoroOnu-Koro was the earth engineers' city, where underground isolation created one of Mata Nui's most self-sufficient settlements, until the Bohrok came. and worked as a Lightstone Miner, an occupation he shared with Taipu. He held the key to the Cavern of Light, a chamber studded with many Lightstones that was the primary source of the luminous crystals for Onu-Matoran miners. The cavern's entrance was sealed by a stone door that could be opened only by Kaj's key. At one point its access tunnel was flooded by a rogue lava flow from Ta-Wahi, leaving the Onu-Matoran unable to reach new supplies of lightstones.

Kaj also served as a Guard and was a member of the Onu-Koro Ussalry, the military force commanded by High Commander Onepu and including Taipu, Nuparu, and Damek. As an Ussal RiderUssal RiderThe Matoran who rode and trained Ussals, managing supply lines and battlefields across both Mata Nui and Metru Nui., he rode Ussal crabs and made use of bamboo disks, pickaxes, and lightstone-spears in battle.

Kaj wears a KanohiKanohiMasks that grant powers and sustain life, they're the most vital artifact in the Matoran Universe. HunaHunaThe Kanohi Huna granted full invisibility to its wearer, with the limitation that the user's shadow remained visible and detectable. in its Noble form and now resides on Spherus MagnaSpherus MagnaA desert world of ancient conflict that became the merger point of the Matoran Universe and Bionicle's true endpoint..