"A tangled, twisted cord of solid protodermis links Mahri Nui below to Voya Nui above. Inside the cord is a complicated and partially flooded tunnel network, home to both land and sea Rahi."
— Toa Helryx, World
The Cord was formed by molten protodermis flowing from Mount Valmai, which cooled and acted as an anchor, securing Mahri Nui on Aqua Magna. It also kept the island of Voya Nui from drifting through the ocean.
The Toa Inika traveled through here to reach Mahri Nui in search of the Kanohi Ignika, and fought the Zyglak that lived there. During the battle, the Zyglak took advantage of the Cord's spiral nature to disappear and reappear and spontaneously attack the Toa.
Vezon also ventured down here to take revenge on the Inika, causing a fight in which he smashed Matoro's head into the wall. Jaller burnt Vezon's Spear of Fusion, and Vezon ended up captured by the Zyglak. While the Toa Inika were traveling down the Cord, Matoro released his spirit to scout ahead and had his body taken over by the essence of Makuta Teridax who attempted to jeopardize the Toa's mission. The other Toa Inika discovered this however, and forced him out of Matoro's body by threatening to destroy it.
When the 300 foot long Venom Eel heard the noises coming from the Cord, its instinct told it that there was food, and it then squeezed the Cord, causing cracks through the maze and partially flooding it.
The band of Zyglak that lived here were killed when the mutated Piraka came down while the Toa Mahri were evacuating the citizens of Mahri Nui. While they were able to defeat the Toa, Axonn intervened, and saved the Toa, sending the Piraka to Daxia. Axonn then led the Toa to a secret chamber which held the Toa Terrain Crawler. The Toa Mahri then used it to speedily make it back to the Pit.
In order to complete their mission, the Toa Mahri destroyed the Cord after evacuating the Matoran to Voya Nui so that the island could return to the Southern Continent, resulting in the destruction of Mahri Nui.
|Mahri Nui Fortress (Matoran Council Chamber) | Matoran Holy Sanctuary | Octo Cave | Pillars of Salt | Fields of Air | The Cord|
|Solis Magna||Spherus Magna (Aqua Magna | Bara Magna | Bota Magna) | Red Star|
|Metru Nui (Maze of Shadows) | Karzahni | Zakaz | Xia (The Mountain) | Northern Continent (Tren Krom Peninsula) | Artakha | Stelt | Odina | Southern Continent (Voya Nui, Mahri Nui) | Karda Nui | The Pit | Destral | Nynrah | Tren Krom's Island | Visorak | Daxia | Southern Islands (Artidax)|
|Field of Shadows | City of Silver|
|The Melding | Spherus Magna | Toa Empire | The Kingdom|
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