I have my own Mario comic series, and my newest character is still unnamed, because I can't think of a name for him, so you'll have to help me out there.
He was created when E. Gadd was showing his cloning device to Luigi, who had needed to clone Peach while Mario was at Bowser's castle for reasons too complicated to explain now. E. Gadd was saying that it still needed work, as it would always alter the clone in some way or ways, sometimes the difference was small, other times it was large. He was warning Luigi that he had better not use it now, or Peach's clone might be nothing like her until Gadd could find the missing component. As he opened it up to show to Luigi the problem, Wario and Waluigi meanwhile were nearby, running from the cops for causing their usual trouble. They had no idea where they were, but they happened to be right by Gadd's house. They didn't realize anyone was inside, and as they ran full speed to the door so they could hide in the house, Wario stumbled as he was pulling the door open, causing Waluigi to trip on him, though not fall over, but continue to slip and slide on the wet floor due to E. Gadd having cleaned the house before Luigi came. When Waluigi turned around, he was so dumbfounded to see Luigi and E. Gadd sitting by some machine, their mouths gaping wide open, he lost his balance completely, and fell forward into the cloning machine. Wario was still on the floor the whole time, oblivious to what happened. A few seconds later, two people stepped out of the machine: Waluigi, and a similarly tall and lanky fellow, though his overalls were storm gray, and his shirt and hat were navy blue, the upside down L on his hat black. The mustache was almost the same, though it stuck out more than up. The rings under his eyes were black, his ears were even longer and pointier, and his shoes were black. Since he had no name, everyone just referred to him as "Waluigi's clone". His voice is less nasal and more evil sounding than Waluigi, and he himself is even more evil than Waluigi. Now, another side storyline in the series to keep track of...