Zomom Nega is the alternate universe counterpart of the canonical character Zomom, hailing from the same universe as Eggman Nega, the Sol Dimension. There were in fact nega versions of all of the canonical Sonic characters in this universe, not just Eggman. The reason most alternate universe versions of characters are unseen is because the majority of them have been killed already.
Zomom Nega is the current leader of the Deadly Six Nega. Like Eggman Nega, he is far, far more intelligent than his main universe counterpart, and is able to abuse his earth powers to the fullest. Master Zik Nega actually considers Zomom Nega his favorite rather than despising him, and used lots of fatty food based products like donuts and sandwiches to levitate around rather than fruit. Zor Nega actually was normally quite cheerful and happy, but had it beat out of him and became even more emo than his regular universe counterpart. Zavok Nega is largely the same as his normal counterpart, but when Master Zik Nega chose Zomom Nega to be the leader, he was outraged and challenged Zomom Nega to a duel, which resulted in him getting eaten. Zeena Nega actually doesn't care about her appearance at all and thinks she is ugly, but is forced to keep up her good looks in order to appeal to Zomom Nega. Because the Deadly Six Nega must always have six members, Master Zik Nega required Zeena Nega to bear children for Zomom Nega. Together, they had a single son, whom was named Zionichute Nega.
The Deadly Six Nega went to nega earth in order to obtain the Nega Chaos Emeralds and Nega Master Emerald. Nega Zomom casually consumed the Master Emerald first while the rest of his team fought Nega Knuckles. Nega Knuckles was even stronger, larger, and much dumber than his Sonic Boom counterpart, though, standing at 8 feet tall, so he did prove to be challenging for the other members of the Nega Deadly Six. He was so dumb, though, that after Nega Zomom ate the Master Emerald, he went inside Zomom Nega's stomach to try to retrieve them, casually getting eaten.
When he fought Nega Sonic over the third chaos emerald, the nega hedgehog was forced to try to run away. Nega Sonic could not run faster than Nega Zomom could dig, like the real Zomom, though, and he was sucked down into the depths of the earth and never heard from again. This caused Nega Amy to commit suicide due to his passing, as her obsession with him was her only notable character trait.
When retrieving that damn fourth nega chaos emerald, Nega Zomom had to fight Shadow Nega. With Nega Shadow's ability to stop time, he was able to actually escape Nega Zomom, as while fast he was not faster than time itself. Zomom managed to acquire the rest of the chaos emeralds besides Nega Shadow's, and came up with the solution that to eat someone who could stop time, he had to consume time itself. He made a deal with Eggman Nega that he would not eat him if he gave him access to the Time Eater Nega, and by eating that Zomom Nega was able to "stop" time by eating it. Using this, Zomom Nega was able to catch and devour Shadow Nega. A side effect of consuming time was that the paradoxes from Sonic 06 Nega did not actually happen, meaning Mephiles Nega and Iblis Nega were deleted from existence, indirectly eaten by Zomom Nega.
It was around this time that Black Doom Nega and the Black Arms Nega invaded Earth Nega. They were obviously very unprepared for Zomom Nega after he had consumed all 7 Nega Chaos Emeralds, but there were enough of them that the black arms were able to kill a significant amount of earth's population before Zomom Nega killed them. Zomom Nega was outraged with the concept that another race wanted to eat the nega humans of nega earth, when their delicious nega flesh belonged to him. Due to defeating the Black Arms Nega, Zomom Nega was hailed as a hero, which left a bitter taste in his nega mouth. He declared himself Nega Earth's new ruler with minimal resistance and quickly turned the nega public's perception of him by enforcing a new law. Anybody caught eating other than Nega Zomom was to be put to nega death. This law resulted in the inevitable deaths of most of the rest of the nega cast. While the law was not meant to apply to the Nega Deadly Six, Nega Zor used this as an excuse to kill himself, forcing Nega Zeena to have to give Nega Zomom a second son named Zamie Nega.
Eggman Nega's domain extended into Blaze's kingdom, and is the sole reason she is lucky enough to still be alive. While Zionichute Nega followed in his father's footsteps, Zamie Nega took more after his mother and grew up to have more effeminate tastes. Zomom Nega tried to get him into eating contests, but he could only devour one plate's worth of food per entire contest, and was an embarrassment to Zomom Nega. Zamie Nega eventually defected from Zomom Nega and made contact with Blaze, whom eventually trusted him enough to show him the canonical Sonic universe. Zamie Nega knew his father would eventually break the pact with Eggman Nega and come kill Blaze, so he specifically had Blaze destroy the portal so that such a horrible villain as Zomom Nega could not hurt his newfound beloved friends.
Zomom Nega only devoured all of the primary worlds in his own universe because he actually did already know about this portal, knowing there was more for him to devour in the world beyond. He was outraged when he learned of Nega Zamie's betrayal.