Portal was a futuristic city located on Angel Island in the altered version of the Light Mobius future timeline. Portal was constructed on Angel Island as a major city that served as the central point of travel and transport between the island and the surface. Many goods and people not originally from the island became established there and the city grew to a massive, multi-cultural hub. Following the timeline alterations, Shadow took over and moved the world capital to Portal, ruling from the newly-built Castle Mobius. When he was removed from power, King Sonic, Queen Sally and their children Sonia and Manik took up residence in the castle. Later, Lien-Da and the Dark Presence were able to invade Castle Mobius and bring Shadow out of suspended animation. (SU: #5)
Portal is generally depicted as a large, futuristic metropolis, somewhat similar to the Echidnaopolis of the past. During Shadow's reign, the city was littered with statues depicting an angelic Maria Robotnik as well as posters informing the populace "The Chaotix are watching."
- Guardian Tower, Guardian training center
- City Center, location of a Maria statue
- Locke's Park, a natural location named for Knuckles' father
- Castle Mobius, seat of Mobian government
- The Chaotix posters are similar to those used in George Orwell's distopian novel 1984.