During the Core War, Atero was made a neutral area, free of raids or attacks. After the Shattering it remained a symbol of hope for the Agori. However, the area eventually fell prey to Bone Hunter raids.
During the most recent tournament, the Skrall failed to appear, puzzling Metus, Berix, and Raanu, although Metus was faking his confusion. Leaving to investigate, they noticed a sandstorm brewing. It soon became apparent that it was actually an army of Skrall warriors advancing towards the arena, who quickly attacked, took control of and destroyed Atero.
Atero was situated on a strip of land in the middle of the Skrall River and made accessible by a bridge spanning the eastern side of the river. Vast quantities of sand rush by in the river, giving the semblance of a waterfall.
- Riddle of the Great Beings (First Appearance)
- Empire of the Skrall (Mentioned Only)
- Comic 2: The Fall of Atero
- BIONICLE: Raid on Vulcanus (Mentioned Only)
- Comic 3: A Hero Reborn
- BIONICLE: The Legend Reborn (Book) (Mentioned Only)
- Sahmad's Tale (Mentioned Only; In an Illusion)
- The Powers That Be (Mentioned Only)
- BIONICLE: Mata Nui's Guide to Bara Magna (Mentioned Only)
- Glatorian Mini Movie
|Aqua Magna << Bara Magna >> White Quartz Mountains|
|Atero (Arena Magna) | Vulcanus (Arena Vulcanus | Vulcanus Lava Flow) | Tajun (Arena Tajun | Underground Lab of the Great Beings) | Tesara (Arena Tesara | Hot Springs)|
|Aqua Magna | Bara Magna | White Quartz Mountains | Black Spike Mountains | Northern Region | Bota Magna | Northern Frost|
|Solis Magna||Spherus 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) | Karda Nui | The Pit | Destral | Nynrah | Tren Krom's Island | Visorak | Daxia | Southern Islands (Artidax)|
|Pocket Dimensions||Field of Shadows | City of Silver|
|Alternate Universes||The Melding | Spherus Magna | Toa Empire | The Kingdom|
|Characters | Sapient Species | Locations | Flora | Fauna | Objects | Powers | Vehicles | Society | Events|
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