Saeras Islet is one of the surrounding islets of Metru-Nui. It was used as the Kin base until it was destroyed. A couple weeks after the base's destruction, a group of Toa (calling themselves the Lightbringers) descended upon the island and began building their own monastery. After initial tensions between them and the former inhabitants, the Kin, had settled down, the Lightbringers began their work on jumpstarting the charred island. They named the island Lightbringer Isle, and it is currently the main headquarters of the Order of the Xa-Kûta. There is also a top-secret base occupied by the Counter Assault Shield under the monastery of the Lightbringers.
Once word had arrived of Santun and Anarchists infiltrating Metru Nui, the Lightbringers activated a powerful shield around the entire island to prevent any unauthorized entry. The only way to get into the city during that time was if someone from the inside let them in.
The defenses were for naught, however, as the island was once again destroyed after an ambush attack from the Menti. The Lightbringers moved their temple and to the resurfaced city of Xa-Koro (in Po-Metru).