Seymour (also known as Evil Simon and Anti-Simon) is the evil version of Simon Seville. Unlike Simon, who is very intelligent, Seymour is quite dim-witted. He also speaks with a southern drawl. The frames of his glasses are a differnent shape than Simon's. In The Chipmunk Multi-Verse Seymour is One of the Darkmunks and rules the Darkmunk Universe Along with his brothers and The Darkettes although he doesn't seem to know this. Seymour has The Dark Elemental Power of water, but barely knows how to control it. He has the ability to control the darkness within people, but he doesn't even know that, all he knows is that he can make the darker part of a persons personality come to the top. Melvin doesn't send him out on missions usually because he almost always ends up messing it up.
Simon lived with is family in the woods for several years before they met any humans. Simon and Chelsea found a unconscious human who just so happened to be Ian Hawke (Darkmunk Universe). When Ian came to the family to become real-life singers, Simon was immediately on-board. Simon enjoyed the attention he was getting from being a major star, but was worried by how much the Darkstars wanted to be around them. Once he learned that they were trying to corrupt Alvin and turn him evil, he tried but failed to keep him from being corrupted. Simon left with his brothers when they left to join the Darkstars as the Darkmunks, claiming that he was going to try to keep Alvin and Theodore safe and out of too much trouble, taking the name Seymour at that point. When Dav gave the Darkmunks their final test, to kill their parents, Seymour didn't think that Alvin was that loyal that he would do it. He was suprised that Melvin actually attacked and beat his father to death. Simon then convinced Melvin not to kill his mother claiming that she wouldn't be a threat and that the trama would torture her for the rest of her life, which Melvin agreed. They then left to report back to their new 'father'.
Water Manipulation - Seymour has the power to control Water in any form, including absorbing the water vapor in the air.
People Corruption - Seymour has the power to control and enhance the Darkest part of a person's personality when he comes in contact with them, including putting the Darkest part of a person as the part that is in control of them.
Immortality - Seymour cannot age nor die, but a limitation that he (and all the Darks have) is that they cannot have natural offspring.