Marcus "Gearhead" Dubrovski is a Ronin Vanguard mechwarrior in Battletech.
Marcus Dubroski grew up on the streets of Cluff's Stand. While he didn't always get enough to eat, he managed to find ways to make himself useful to local tradesmen who wanted him to have a future. They clubbed together to send him to the best technical school in the system.
He graduated with honors but even that can't create opportunities out of thin air. Without any other options, he enlisted in the planetary military. Unfortunately he enlisted approximately one year before the entire military organization collapsed due to lack of payroll. Markus stole a truck full of hardware, sold it via a friend on the streets, and headed off planet to Solaris VII. There he signed up for an apprenticeship at a stable with openings, went through comprehensive training with other rookies, and survived his first public bout.
He soon realized that he wasn't a fan of people cheering when he lost. As soon as he paid off his training debt, he moved on from Solaris VII to the Periphery, where he now makes a living as a mercenary. He makes friends easily and finally seems content with the life he's made for himself.