Replikas are recreations of the original sectors that were created by X.A.N.A. Their existence was first discovered in Maiden Voyage, and more detail came into place about them in the episode Replika. The only way to destroy them is by destroying their supercomputer which is located somewhere on Earth, usually in a location relevant to the Replika's environment. There were ones in Siberia, New Mexico, the Amazon jungle, and the last was in space.
Lyoko is powered and sustained by a supercomputer. To host copies of Lyoko, different supercomputers would be needed. X.A.N.A. takes control of abandoned supercomputers to host Replikas and the surrounding area to produce various things for its eventual plan for world domination.
The supercomputers that contain the Replikas are located in environments similar to that of the sector that the Replika copies. For example, Forest Sector Replika supercomputer is located in the Amazon Rainforest. The Desert Sector Replika supercomputer is located in New Mexico. The Sector Five Replika supercomputer is located in space aboard the International Space Station. The Ice Sector Replika supercomputer is located in Siberia. The only known Replika for the Mountain Sector appears in the video game Code Lyoko: Quest for Infinity, but not in the animated series. However, a background design was initially created for it, featuring a large dam up in the mountains.
It's debatable if the Volcano Replika and Cortex are Replikas or not, given that they don't duplicate a Lyoko sector, instead using their own design. They are still however, referred to as Replikas. It's possible that the original sectors these presumably replicate were once parts of Lyoko, and were deleted before the Factory was discovered by the Lyoko Warriors. However, it's more than likely that the custom design of the Volcano Sector was made by X.A.N.A. itself, whilst the Cortex was designed from blueprints Professor Tyron had stolen from Franz Hopper.
It was discovered in Cold Sweat that X.A.N.A. had infected and controls hundreds of supercomputers all over the world, meaning that destroying each one one by one was not an option as that would take a long time, which is why the X.A.N.A. Destruction Program was written by Jeremie and Franz Hopper. When that program was launched in it's final form, it is almost certain that it destroyed every Replika in the Digital Sea, with the exception of the Cortex. It didn't destroy the Cortex because it wasn't registered as a X.A.N.A. creation.
Logically, there would only be five actual virtual worlds that can be considered Replikas, which they would be the ones based off of Lyoko's sectors: the Forest, Desert, Sector Five, Ice, and Mountain Replikas. The other virtual worlds aren't technically Replikas of Lyoko's sectors, but are still referred to as Replikas to classify them.
Replikas are compatible with most of the software built for the Supercomputer. This includes the devirtualization and materialization programs, vehicles, and programs related to towers. However, any program that requires interfacing with the Factory's Supercomputer requires a link of some form, usually the Skid.
It is unknown when the first of any of the replikas were created by X.A.N.A. since their existence was never known until the maiden voyage of the Skidbladnir, but it is quite possible that they have been around since some time between The Key and Straight to Heart after X.A.N.A. stole Aelita's memory and the Keys of Lyoko and escaped the supercomputer, as the first one was located by the Superscan in Straight to Heart, but it was not discovered until A Lack of Goodwill.
List of Replikas
|Sector of the Replika||Supercomputer on Earth||Destroyed by||Episodes in which it appears|
|Forest||Amazon rainforest (South America)||Odd|
|Desert||New Mexico (North America)||Ulrich|
|Sector Five||International Space Station (ISS)||Odd & Yumi||
|Ice||Siberia (Asia)||Multi-Agent Program|
|Mountains||Hydraulic Central of Canada (North America)||Odd & Ulrich||
|Volcano||Heart of a volcano||Aelita & Odd||
|Ice Sector | Desert Sector | Forest Sector | Mountain Sector | Carthage|
|Ice Replika | Desert Replika | Forest Replika | Mountain Replika | Volcano Replika | Carthage Replika|
|Other Virtual Worlds|
|Digital Sea | Cortex | Virtual Limbo | Simulation Bubble|
|Dormitory Building | Administrative Building | Cafeteria | Gym | Track | Park | Hermitage | Science Building | Playground | Garden Shed | Infirmary | Boiler Room|
|Union Base | New Mexico Research Facility | Space Station | Jungle Research Facility|
|Renault Auto Factory|
|Factory Floor | Factory Lift | Lab | Scanner Room | Supercomputer Room | Assembly Room | Security Center|
|Kadic Academy | The Sewer | The Factory | Ishiyama residence | The Pool|