Onu-Koro was a village of tunnels, caves, and mines located beneath the surface of Onu-Wahi. It was inhabited by the Onu-Matoran and Turaga Whenua and protected by Toa Onua. Onu-Koro was the site of protodermis mines and Ussal crab races. The Onu-Suva was located here.4
Notes
Onua, Toa of Earth, and his people dwelled in caves and tunnels hollowed out from the cliffs near the Papu Niho [sic, Papa Nihu] reef. They preferred to stay underground during the light and heat of the day.5
Onu-Koro's Toa was Onua Nuva, its Turaga was Whenua, and its villagers were the Onu-Matoran. Onu-Koro was a village of dark tunnels, caves, and mines that plunged deep beneath the surface of Mata Nui. The Onu-Matoran mined protodermis, competed in Ussal crab races, and listened closely for the vibrations that warned of danger approaching. When the Matoran were in danger, Onu-Koro was a good place to hide. In the worst of times, Onu-Koro tunnels had been used to get messages from one village to another.6
When Onua first arrived on Mata Nui, he found himself in an enormous cavern which was apparently some sort of park. It was lit by rock pillars ending in flat stone platforms, each with a glowing lightstone on top. Dozens of columns stretched up to its high ceiling. Between these columns were paths made of cobblestones set into the earthen floor. Stone benches stood beside the paths. A small, clear stream trickled through the cavern. The little stream emptied into a still, round pool lined with pebbles. In the center, reddish-brown gemstones spelled out "Onu-Koro." A series of tunnels and caverns led from here to another large cavern. On each wall of this cavern, a series of carved-out dwellings climbed nearly to the ceiling. This is where Turaga Whenua could be found. At the center of the cavern was a fountain filled with crystal-clear water. A sculpture of Toa Onua rose out of the pool spouting water from several places.7
Onu-Koro had arched stone gates.8
Although Onu-Wahi appeared uninhabited, the thriving village of Onu-Koro could be found underground there.9
Located beneath the surface of Onu-Wahi, Onu-Koro was the village of Earth and home to the Onu-Matoran. Made up of tunnels and caves, Onu-Koro was known for its protodermis mines and Ussal crab races. It was defended by the Ussalry, Matoran mounted on top of the large crabs. Onu-Koro was damaged by the flood caused by the Bohrok and later destroyed by the Rahkshi.10