|Primary Residents||Manas, Dust Darter|
|Former Residents||Karzahni, Matoran|
|Location||South of Metru Nui|
|“||It's a warning. It reads something like this...'This is a realm of shadow...of famine and plague and blight...This is a world of darkness...and there is no place for light.'||”|
–Hahli, BIONICLE Legends 2: Dark Destiny.
Karzahni was a realm in the Matoran Universe with strange geographical features. In Matoran legend, it was where lazy and poor workers were sent and tortured by its ruler Karzahni, after whom the land was named. However, in reality, it was a place where damaged Matoran would be sent for repairs.
Karzahni was created as part of the Matoran Universe over 100,000 years ago by the Great Beings as a place for Karzahni to fix Matoran who were damaged or didn't function properly, then send them back to where they came from. However, Karzahni did a poor job with his repairs, leaving the Matoran weaker than before but giving them weapons to compensate. Ashamed of his shoddy work, he did not allow the Matoran to return to their homelands. Instead he sent them to other regions of the Matoran Universe.
Over time, due to the fact that those who were sent for repairs were not returning, Matoran stopped being sent there. In response, Karzahni stopped sending the rebuilt Matoran away, instead preferring to keep them as his prisoners. With no Matoran going to or returning from Karzahni, the land and its ruler eventually faded into legend among Matoran.
After the Matoran Civil War, Makuta Icarax was assigned by Miserix to watch over the island. Icarax did nothing to intervene in the plight of the Matoran trapped there, feeling that Matoran who were sent to Karzahni were not worth helping. Icarax later left Karzahni with some of the realm's Manas crabs in an attempt to steal power from Teridax in the aftermath of the Great Cataclysm.
Jaller, Kongu, Hahli, Hewkii, Matoro, Nuparu, and Takanuva later traveled to Karzahni, as part of the route to Voya Nui. However, a barrier of light cut off Takanuva from the six Matoran. After traveling through part of Karzahni, they encountered the ruler, who captured them, replaced their Kanohi, and had Hahli tell him about what was going on outside his realm, while the others were forced into working.
The group later escaped when Karzahni gave the Matoran a vision of the worst possible outcome for the universe, which stunned the ruler temporarily. This gave them enough time to enter the Toa Canisters they had found earlier and set off.
Karzahni was destroyed when Gali summoned a Nova Blast to fight Icarax. All in the realm was destroyed except Toa Lhikan's Noble Hau. Pridak also went to Karzahni to discuss an alliance with "The Shadowed One".
During Teridax's reign of the Matoran Universe, Tahu, Kopeke, Lariska, "Guardian", Johmak, and Krahka assembled a camp in Karzahni where they could organize themselves against him. During their debate of their next move, Teridax discovered them and killed a straying "Guardian" by bonding him with earth and sealing him in a crevice. A dozen Exo-Toa arrived afterward, and the group commanded to accompany them to Metru Nui to either be killed or forced into slavery. They were then rescued by Onua.
Karzahni was abandoned after the inhabitants of the Matoran Universe evacuated to Spherus Magna after the death of Teridax.
The ground screamed at every step and it constantly emitted heat greater than that of the Great Furnace of Metru Nui. Other land features included volcanoes that spewed burning ice, ripples on water sounding louder than thunder, and waterfalls that were made out of dust rather than water. Additionally, if a Matoran was too lazy and sat down, the rock which the Matoran sat upon would turn the Matoran into a statue.
There was also a room in Karzahni, where a lone Av-Matoran worked on building Toa Canisters.
The realm was once accessible by boat or airship. However, the waterways later dried up and could only be reached through an overland path infested by Manas.
- Karzahni was the supposed birthplace of the Dark Hunter codenamed "Devastator", who was reputed to have emerged from a fiery crevice in the region.
- As part of the Great Spirit Robot's anatomy, Karzahni was located within its neck.
| Mata Nui • Metru Nui • Karzahni • Xia • Zakaz • Odina • Northern Continent • Southern Continent (Voya Nui • Mahri Nui)|
Karda Nui • Destral • Daxia • Stelt • Artakha • Tren Krom's Island • Nynrah • Visorak • The Pit
Southern Islands • (Artidax • Keetongu and Tahtorak's Homeland)