He was born from a bit of ash dust by Geemina. He first appeared in the series to attack Mario and Luigi. He kidnapped Luigi for Mario to give up his coins and power ups to gain power for himself. He also had a different army of helpers before the Fakans. It's also hard to kill him. His head was cut off, but he survived and regrew it.
Past Error Weegee
With Mario winning the battle, Error Weegee has to go back to the past, and retry this whole battle thing again. During this, he meets his past-self. He absorbs his past-self. He claims he won't die, but he will suffer. He then takes Negative Mario from that timeline back to the present.
Error Weegee is one scary and evil villain. Mind as well consider him worse than Hitler. He was born with godly powers and so he abuses them. He wants to destroy humanity. Weegee and Aaron worked together in episode 2.5 to take him down and it went nowhere.
He can warp time, teleport, run really fast, go through powers, and even use Portals to warp punch you. He also can take away powers... One scary attack is he can explode things with his mind. He abducted Dan for experiments and then sent him into the Backrooms. He worships the Illuminati too, and even sold his soul to him.
He was later told by Illuminati to cause more chaos. He went after AGK, Aaron, Pete, Ashley, and Olivia. It was mainly all 5 because Aaron panicked, and he told them about his comeback. He had thought AGK was dead, but he underestimated him. He mocks him always for being a kid. He went right after AGK and punched him so far away. Next target was Aaron. He oddly warned him he could not fight alone, but Aaron ignored. He put his head threw a Portal, and blasted a giant laser out the other portal. This damaged Aaron badly. He then went after Pete. He is so strong, he ripped Pete's arm off, killing him from blood loss. AGK got very mad, and threw punches, but it didn't do anything. His final target was Ashley. AGK and Ashley worked together to finish off Error Weegee.
Out of nowhere, he called AGK on his phone. This was a warning to AGK, that if AGK doesn't let him free, he will free himself eventually to kill his family. He also appeared in Weegee's imagination while Weegee was fainting slowly to death. He asked to be let out.