Eggman Nega

Doctor Eggman Nega (or simply Eggman Nega or Doctor Nega) is a major antagonist from the Sonic the Hedgehog series and the arch-enemy of Silver the Hedgehog and Blaze the Cat. Originally, Eggman Nega was believed to be an alternate-dimension counterpart of Dr. Eggman from the Sol Dimension, but it was later revealed that Eggman Nega is in fact a descendant of Eggman. Eggman Nega first appeared in Sonic Rush, as the main antagonist alongside Dr. Eggman, and subsequently appeared in it's sequel Sonic Rush Adventure. He as well appears in as the main villain in Sonic Rivals and Sonic Rivals 2, this time as an enemy of everyone, including Eggman himself. Eggman Nega has appeared as one of Sonic's most recurring foes, alongside Eggman and Metal Sonic.

Mario & Sonic: Worlds in Danger
Eggman Nega appears as a villain in Jmkrebs30's flash series Mario and Sonic Worlds In Danger, being recruited along with several other villains from the Mario and Sonic series. He appears namely in Episode 5 and 6, where he was violently interrogating Yoshi into handing him over a Chaos Emerald, until Mario and Sonic the Hedgehog arrived, and proceeded to battle him. The heroes were evenly matched with Nega's Eggmobile, but were eventually overpowered. As Nega prepared to destroy them, he was interrupted by his two nemesis', Silver and Blaze. The two heroes soundly defeated their nemesis in a short, yet epic battle. Nega then retreated, swearing revenge upon the heroes.