|System Leader||Unknown, possibly Phong|
|Energy Sea Position||Surrounds the City|
|First Appearance||Daemon Rising|
|List of Systems.|
The Twin City was a sister city to Mainframe, they were joined together by the Gilded Gate Bridge. It was nearly the same size as Mainframe itself, and as the name would suggest is virtually identical to Mainframe City except for the smaller Principal Office building in the center. Although joined with Mainframe, the Twin City was also an independent system that functions separately. In the User world the two cities were two computers networked together.
The Twin City Principal Office had similar architecture to Mainframe's Principal Office, and like this one in its sister city was the central operating center.
The building housed its own System Operating Core, the Core Control Chamber, the cities Central Archives along with a large Auditorium. Unlike the Mainframe counterpart, there was no Sub-Sphere visible atop it. The Twin City cannot survive without its Principal Office.
It is unknown if the Twin City had its own city administrator, or if both cities were lead by Phong.
Instead of being perfectly symmetrical with each other, the Twin City had its six sectors laid out counter clockwise starting from both their Floating Point Park sectors.
Professor Welman Matrix had long dreamed of the Net, believing there were other Systems beyond Mainframe. A theory that won him many critics among Sprites in the Twin City who strongly believed nothing else existed within Cyber Space.
He needed to get proof and so constructed the Gateway Command inside the Twin City's Principal Office Auditorium and unveil its findings to a Sprite audience, conducted in an experiment. This would have allowed Mainframers to visit these systems.
Professor Matrix soon unveiled the Gateway Command at a large conference held in the Twin City Principal Office. A huge audience of Sprites attended the demonstration. When Welman activated the Gateway it locked onto the largest energy source outside of Mainframe, the Super Computer and the powerful Super Virus Gigabyte. It accidentally brought him to the city. Gigabyte's energy overloaded the Gateway Command in the process. The resulting blast damaged the Twin Cities Operating Core, causing it to explode, destroying the rest of the city. A powerful shockwave spread out from the Twin City, damaging Mainframe. The explosion had nullified everyone in the Twin City and tore apart Gigabyte into two viruses, Megabyte and Hexadecimal.
All that is left of the beautiful city is a tiny island now named Lost Angles. It is still connected to Mainframe by the Gilded Gate Bridge, now horribly twisted. Hexadecimal took the island as her home as she found the ruin's chaotic nature to her liking. She added a massive tower to the island's ruins, naming it her Lair.
When Mainframe crashed following Megabyte's defeat, the Twin City was restored alongside Mainframe when the User restored Mainframe's backup. It is present in Daemon Rising.
- The most widely accepted theory about the Twin City disaster is that Mainframe and the Twin City were two computers networked together and that when the Twin City was destroyed that computer had a hard drive meltdown, making it unrecoverable.
- The Twin City was first mentioned in the episode AndrAIa.
- The first time the Twin City was seen was in the episode Daemon Rising.