Sky Temple Keys are required to enter Sky Temple, and there are ten keys in all. The Luminoth sent their greatest warriors to retrieve the keys and invade Sky Temple to finish off the Ing, but most were killed shortly before they could acquire the keys. One warrior had managed to retrieve a key and return it to the Sky Temple Gateway, located in the Dark Temple Grounds. Before she met her doomed fate she left behind clues leading to the locations of the other warriors, which can be found all throughout Light and Dark Aether.
Samus returning the Sky Temple Keys
- "One of nine needed to open the Sky Temple" —Scan data (Metroid Prime 2: Echoes)