The Evil Twins are the main antagonists of Crash Twinsanity.
Warning! Spoilers Below!
The Evil Twin's story start at Madame Amberlys Academy. Neo-Cortex was working on a prototype Evolvo Ray, until when a student threw a knife at him. He didn't realize it, and the knife missed him, but it hit the Evolvo Ray. When he tried it on his pet birds, Victor and Moritz, they disappeared,they were sent to the dimension where Evil Crash lived. He didn't find them though. They were evolved by the ray, so one of them decided to get revenge. They tried to kill Cortex and Crash years later, and they tried to destroy Insanity Island (ironically, in the other dimension, the name of the island is the same as the game name, Twinsanity). They failed to do so when Crash and Cortex teamed up to defeat them. After the final fight, they made a retreat and they ended up in Evil Crash's house, where he devoured them.