Angel Island (Sonic X)

Angel Island (エンジェルアイランド) is a location that appears in the anime series Sonic X and its comic series published by Archie Comics. It is an island from Sonic's world that floats through the skies, suspended by the mystical powers of the Master Emerald. It is also the location of its world's Planet Egg. The island is the ancestral home of the Knuckles Clan who has protected its magical gemstone for generations, its current guardian being Knuckles the Echidna, the last known survivor of the Echidna race.

Due to Chaos Control, Angel Island was sent to Earth for a while before being returned to its home world. Following the Metarex wars, the island was left grounded until the Master Emerald could recover from recent usages.

Past
Angel Island came into being generations ago, where it was a part of the Mystic Ruins. When the ancient Knuckles Clan, an echidna clan led by Pachacamac yearned for the Master Emerald and Chaos Emeralds, which rested at a shrine on the outskirts of their settlement, he planned to seize the Emeralds to obtain ultimate power for his clan. When this time came, Pachamac's daughter, Tikal, stood between them, and begged her people to leave the Emeralds to protect the peaceful colony of Chao that resided there. When the clan continued onward regardless, this angered the Emeralds' guardian, Chaos, who appeared and wiped out the echidnas as Perfect Chaos. Tikal prayed to the Master Emerald to calm Chaos down when its rage became uncontrollable. In response, the gem absorbed both of them into itself. In the aftermath, a large fragment of the surrounding land had broken off and floated into the sky, becoming Angel Island. The remaining Knuckles Clan members would then take residence there to protect the Master Emerald. Generations later, the only echidna left on Angel Island to uphold this duty would be Knuckles the Echidna.

Chaos Emerald Saga
Eventually, Angel Island was left unoccupied when Knuckles got sent to Earth by Chaos Control. While traveling the Earth, Knuckles desperately searched for a way to get back to Angel Island and his duty.