Melvin Fett (GoS)

Credit to @D-Skelton

Born as a clone on Kamino, he suffered a rare mutation that caused him to age slower than normal, rather than faster. He was taken and studied by Nala Se, who moved him off-world before the destruction of Kamino. Eventually, he ended up in the care of a regular family and grew up somewhat normal. By the time he was an adult, he had become a crewman on a smuggling ship, living very uneventfully. Ultimately, he wound up working as a bounty hunter, stealing a set of Mandalorian armor, painting it, and telling employers he was the son of the legendary Boba Fett. Boba Fett would eventually come face to face with him, initially wanting to kill him, only to discover he was a Jango clone like himself. Boba ended up allowing him to join him on his quest to reform Mandalore under a single united ruler, a task that would not be easy.