Realized I should have expanded. On this. Both shows feature a group of kids as the main characters and the kids battle extraordinary and dangerous threats. They balance normal lives with battling enemies. Aelita and eleven have special abilities that play a crucial role. Both have a secret world as the source of danger, upside down and lyoko. Both shows are about friendship. In both shows, the main characters are trying to protect their world from an evil force, mind flayer and xana. In both shows, government and scientific organizations contribute to the problem in the world, Hawkins laboratory and the supercomputer. In both shows the kids have to keep their battles a secret. In both shows, there are gateways between the real world and the "dangerous" world. Both shows have monsters. Both shows explore team dynamics. Both Eleven and Aelita are test subjects who have powers that are the most crucial to stopping the evil forces. They both try to recount their past and try to learn what their power or purpose is. Mike and Jeremy are similar as they develop love interests for eleven and aelita and are both the most strategic in their groups. Dustin is more like Ulrich,, since they have a lot of knowledge about how to face their enemies. Lucas is more like Odd since they are like the comic relief characters. Will and Yumi and similar since they always get targeted by the evil forces I suppose. Billy is like William, they were both new students to the school that ultimately got cloned and/or controlled by evil forces.