The Red Star is a mysterious celestial object in the Matoran Universe.
The Red Star was created by the Great Beings, along with the Mata Nui robot. Its purpose was to give the Robot energy to fly, attaching to his back and working like a backpack. When it was not in use (like on Aqua Magna) it orbited around the Matoran Universe. When the robot was shut down by Teridax, it remained in the skies of Aqua Magna.
On Mata Nui it was used by Matoran and Turaga to predict the future, by watching the position of other stars around it. This could be done using various telescopes on the island, including one in Ta-Wahi and Nixie's in Ga-Koro.
Later, the six Matoran who would later have become the Toa Inika were fleeing from Karzahni inside Toa Canisters. When they washed ashore the island of Voya Nui, Lightning from the star struck the canisters and changed the Matoran into Toa Inika ("Inika" means "energies from a star").
Gali was later tasked to record the position of the Red Star, as said in the Scroll of Preparation for the reawakening of the Greas Spirit. While doing it, she activated her Akaku Nuva to zoom inside the star, and discovered that there was something alive inside it.
The Red Star could also be seen from Bara Magna. When the Agori Tarduk was cleaning up Arena Magna, he found a piece of metal on which the only thing colored was the Red Star. Tarduk then convinced a fellow Agori Crotesius to help him in searching for the Red Star in the northern regions of Bara Magna, where it was shown on the map.
Now that Spherus Magna has been reformed, the Star orbits around it.