Pre-Super Genesis Wave
Hailing from Iceborough, capital of the Walrus Herd, Rotor's family relocated to Mobotropolis in search for a better life. Unfortunately, the family was torn apart during Dr. Ivo Robotnik's military coup. Young Rotor was sent to Knothole Village with many other children in the city while Rotor's father Sherman Walrus was killed in the invasion. Rotor's pregnant mother Georgette Walrus survived the coup but moved back to Iceborough, leaving her son Rotor at Knothole.
Years later, Rotor became a member of the Knothole Freedom Fighters and aided the team with his mechanical expertise. Rotor's fondness for heavy weapons and the occasionally explosive results of his engineering feats soon earned him the nickname "Boomer". Rotor's smarts even earned him a seat on the Council of Acorn during the Freedom Fighters continued conflict with Robotnik's Empire and beyond. However, when Rotor decided in using his brilliance to build more powerful weapons in the war against Dr. Eggman, it lead to his creations harming both friend and foe. Ashamed, Rotor vowed never to make another weapon again, although he later feels that he'd broken this vow after helping construct the Metal Sonic Troopers in order to defend Knothole Village.
Eventually, Rotor "retires" from his role in the Freedom Fighters because of long term injuries he had sustained when saving Tails from a collapsing ceiling. Rotor was then elected into the new Council of Acorn, and started to have issues with some of the decisions the new council was making, which later leads him to resign out of protest. However, with the Knothole Freedom Fighters currently disbanded, Rotor soon returns before the council along with Sonic the Hedgehog seeking permission to start two new teams; Team Freedom and Team Fighters.
With the council's approval, Rotor became the leader of Team Freedom, who protects New Mobotropolis, while Sonic leads Team Fighters, who battles the Eggman Empire. Rotor's return to active duty is now possible thanks to a special Nanite suit that supports the injured areas on his body, allowing Rotor to physicality fight alongside his teammates on missions again. Eventually, Team Freedom's abilities would really be put to the test when a transformed Tails Doll threatened to flood the city with pollution.
Post-Super Genesis Wave
Rotor started out his life living in one of the colder regions of the world with his father Tundra the Walrus, who seemed to dislike anything new or different his son would create. Due to his father's abuse toward him and his inventions, Rotor left home in search for a better life at Mobotropolis, only to discover the city under control of the Eggman Empire. However, Rotor soon finds his way to the hidden village of Knothole, where he also discovers that his talents would be much needed there. Eventually, Rotor became a member of the Freedom Fighters and continues to create various inventions that will aid his teammates in opposing the Eggman Empire.