Dr. Eggman Nega, also known as Dr. Nega and Eggman Nega, is a mysterious villain and "mad man" who went to war with the Zone Cops. Traveling across the Cosmic Highway, Nega's actions caused severe chaos across the multiverse. For this reason, the Zone Cops issued a lock-down on the various universes, leaving only a few open to maintain stability. Nega's war with the Zone Cops resulted in massive damage to No Zone. Because of this, the Zone Cops were too preoccupied making repairs to deal with the Suppression Squad's invasion of Mobius Prime. (StH: #189, #197) He is rumoured to be after the Sol Emeralds and the Jeweled Scepter. (CSE)
Dr. Nega would later fly an insect-like aircraft carrying a mysterious capsule containing the Cyan Sol Emerald to the Prime Zone using a portal while being chased by two Zone Cop vehicles. As he fired at the Zone Cops, one of them fired at the craft's legs, dislodging the capsule. Nega then escaped the Prime Zone using another portal, with the Zone Cops still in hot pursuit. (SU: #21)
Background information
Dr. Nega was never referred to by name in Sonic Universe#1, though his silhouette can be seen in the issue, and notably, he appears to have a similarly shaped body to that of Dr. Eggman. It was only hinted that he was Dr. Nega in one of the caption boxes in Sonic the Hedgehog #197.
Dr. Nega's full name is Eggman Nega. However his appearance and full name are currently limited in the comics due to issues with SEGA, but Ian Flynn hopes that that will be rectified in the future. (1)
Fans often debate if the Eggman Nega from the Sonic Rush series is the same as the one from Sonic Rivals or is a completely different person. They have entirely different origins, he is Dr. Eggman's alternate counterpart in Sonic Rush and in Sonic Rivals he is his descendant.
Curiously, the characters that don't find out about Eggman Nega's "future" origin in the Sonic Rivals series consist of only the characters that have knowledge from the Sonic Rush series about his "dimension" origin.
When Dr. Nega was chased by the Zone Cops, it was mentioned he illegally crossed 47 zones.
Dr. Nega made in unofficial appearance in Sonic Universe 24's Off-panel
His design appears reminiscent of the older Dr. Eggman from the Genesis era, albeit with the colors reversed, a longer nose, a white mustache (suggesting he is at an elderly age), pointy blue sunglasses, and visor-styled goggles instead of normal ones.