Some TMNT stuff really isn't for little kids.
Rocksteady (real name: Maxence; last name not fully revealed, but starts with "Ne") appear (first in human form) in the IDW comics, where they also work for the Shredder and the Foot Clan. In their first appearance they were helping the mutant Alopex, find the secret hiding place of the Ninja Turtles, but by the distrust of Raphael they were eventually thwarted. Finally, both voluntarily adhere to the transformation to their mutant forms, in order to join the ranks of the Foot.
Their origin was finally explained in their villain micro. Rocksteady was a gang member. After he and his buddy Bebop were kicked out of their gang, they joined the Foot Clan and defeated a bunch of other gang members for the honor to become mutants. Rocksteady became a mutant rhino while Bebop became a mutant warthog. After screwing up a job and thinking Karai to be dead Rocksteady suggests that since Karai is dead, they return to Foot Headquarters and just say that she deserted. Karai isn't dead, however, and has overheard the entire mutinous conversation. She sends a bunch of Foot Ninja to kill them. However, Rocksteady and Bebop defeated them and ask for a second chance. Karai than decided to keep them due to their brute strength.
The two mutants were debuted before the Foot Clan near the end of the City Fall arc, when Karai summoned them as reinforcements during a battle with the Turtles. They successfully drove back Splinter, Michelangelo, Raphael and Donatello, but were defeated by April using an antigravity gauntlet. They attempted to pursue, but were driven back by a grenade.
Bebop and Rocksteady were later recruited by Pigeon Pete, who thought they might be good additions to the Mutanimals. However, Hob reacted badly when he saw them, both because they were part of the Foot and because they were originally human. A massive fight broke out between Rocksteady and Bebop and the various other mutants, including Alopex, Michelangelo and Splinter.
They were assigned a more deadly duty in the Attack on Technodrome arc, in which they were assigned to watch over Donatello while the Foot Clan attacked Krang's forces. When Shredder realized Donatello had tricked them, he ordered the two mutants to murder the Turtle. They savagely beat Donatello, breaking his shell open and leaving him for dead.
Rocksteady was one of the Foot Clan representatives during the Gauntlet, along with Bebop, Koya and Bludgeon. He fought Raphael, but the Turtle used agility and tactical thinking to pit Rocksteady and Bebop against each other. When Splinter became leader of the Foot Clan, Bebop and Rocksteady departed for parts unknown.
The two mutants became the center of the Bebop and Rocksteady Destroy Everything miniseries, in which the Turtles find the skeletons of their mutated foes in a museum's prehistoric exhibit. Meanwhile, the present-day Bebop and Rocksteady are in Rio de Janeiro, repeatedly failing to join other gangs. They come into possession of a time scepter and accidentally activate it, causing massive disruptions in time and between different realities.
After that disaster, Rocksteady and Bebop began traveling back to New York, but were temporarily halted when one of Rocksteady's ears reverted back to a human's; he cut it off to keep the effect from spreading. They encountered the monster-hunter Hector Barrales, and accompanied him to find a flying monster in the area. Rocksteady's left arm reverted as he was taken by Wingnut and Screwloose, followed by more body parts as they traveled through the desert.
Having fully reverted, Rocksteady and Bebop decided to try being good people for a change, and attempted to hold down jobs in Houston. Under his true name of Maxence, Rocksteady got a job working at the docks, but the pair encountered Xiang Fei Tong, who attempted to kill them. They were mortally wounded in the battle, but then found by Savanti Romero, who used his magic to heal them and temporarily restore them to their mutant forms. In exchange, he wanted their help to storm the Paradox Presidio and kill his enemy Lord Discordance.
When the Time Lords arrived in Houston, the pair attempted to stop them in scrapper pods, but only succeeded in causing more mayhem and provoking Agent Ravenwood into a fight. They were arrested by the Time Lords just as the spell wore off, at which point it was revealed that the reversion to human was the result of a time distortion caused by Savanti. Anchovy attacked the arresting officers, at which point Rocksteady and Bebop took the opportunity to steal their ship, going on a joyride across the Earth in search of New York. They eventually clashed with Agent Ravenwood again, nearly killing her but being badly wounded in the process. Upon regaining consciousness and returning to the city with Anchovy, the pair encountered Karai, who voiced her intent to reclaim the city.
- Teenage Mutant Ninja Turtles Micro-Series issue 1
- Teenage Mutant Ninja Turtles Micro-Series: Villains issue 4
- Teenage Mutant Ninja Turtles issue 25 (IDW)
- Teenage Mutant Ninja Turtles Micro-Series: Villains issue 7
- Teenage Mutant Ninja Turtles issue 27 (IDW)