The Forgotten Realms, also known as the Forgotten Worlds, are the former homes of the Dragons from the Dragon Realms, making its first appearance in Spyro: Year of the Dragon. It later made a reappearance in Spyro: Shadow Legacy.
History
The Dragons once ruled the Forgotten Realms alongside the Sorceress and her Rhynoc army before the events of Spyro the Dragon. However, the Dragons and the Sorceress didn't get along. One day, when a Dragon Elder and the Sorceress were having a huge argument, she banished all of the Dragons to the other side of the world, which would eventually become known as the Dragon Realms. Since the dragons left, all the magic in the Forgotten Realms had started to dry up. After Spyro beat the Sorceress and destroyed her, all the magic in the Forgotten Worlds returned.
In the Spyro: Year of the Dragon, the Sorceress is the main antagonist of the world.