The Keybearers were a group of ten Luminoth warriors sent to acquire the ten Sky Temple Keys. They were armed with the most powerful Luminoth armor, weaponry, and the Energy Transfer Module to regain the Light of Aether. Most of the warriors were defeated before they could return the keys to the Sky Temple Gateway, though the champion A-Kul managed to return her key.
The equipment used by the warriors was stolen by the Ing, then used against the Luminoth. Before she died, A-Kul left clues concerning the final resting places of the other Keybearers in the hopes that fellow Luminoth warriors might use that knowledge to reclaim the nine missing keys.
- "While our forces on Dark Aether fought desperate battles against superior numbers, our best minds completed their work. The Energy Transfer Module, a device designed to recover our lost planetary energy, was ready at last. A force of our greatest warriors was assembled, each equipped with the best armor and weaponry available. We sent this brave cadre of fighters to invade the Sky Temple and seize the missing energy lying within." —The Final Crusade (Metroid Prime 2: Echoes)
- "A-Kul tried to send me back to Aether, that I might get reinforcements. Both cadres have been attacked, devastated." —S-Jrs's Testament (Metroid Prime 2: Echoes)
- "Soon I shall pass to the final rest. My key is in place. Through my spiritual link to the others, I know where their bodies lie." —A-Kul's Testament (Metroid Prime 2: Echoes)
- "I shall leave this knowledge, that their last location in the dark world can be known. May this knowledge lead our warriors to the Sky Temple Keys.
The time draws near. Hear the words of A-Kul, she they call Champion of Aether. Know that my warriors fought and died with uncommon valor. Do not look unkindly upon their failure, for they died to save us all." —A-Kul's Testament (Metroid Prime 2: Echoes)