Yang Virtanen is the chief 'Mech tech of your team, responsible for organizing your mech roster and whipping your techs into shape.
Yang is a native of the Capellan Confederation and a veteran of the Third Succession War. Born on Bryant, Yang would have enjoyed pale blue skies, emerald-green seas, and a booming agricultural business... If he was born before Stefan Amaris got to it. Enormous orbital mirrors called Storm Inhibitors were responsible for the pleasant climate of Brynat - and since the Star League was responsible for them, Amaris had his troops use 'em for target practice.
Without those mirrors, Bryant reverted to its natural state: a miserable little ball of windblown dirt, actively hostile to human life. By the time Yang came along, the only places where people could live in relative safety were the planet's poles. Of course, you can't fit a planet's entire population into a handful of cities at its poles - there isn't enough space, no matter how far down you dig or how tall you build. His childhood home in a nutshell was way too many people jammed into a tiny, claustrophobic space, with nowhere to go but off-planet. He cleared out of there as fast as he could and never looked back.
He enlisted as a soldier and served with distinction in 2nd St. Ives Lancers, 1st Battalion, under Major Ling. The veteran unit was particularly involved in the fighting and Yang wound up losing his original arm back in 3010, on St. Loris: An agricultural world and a breadbasket for the neighboring systems. Green fields, rolling hills, the perfect place for R&R after the vicious fighting with the Federated Suns on Kittery between 3005 and 3010.
Barely a month into their deployment, the Ceti Hussars arrived to burn them out and finish the job they started. Yang remembers kicking back in the 'Mech Bay, feet propped up on an engine block, sipping on a snifter of Ambergrist Vermouth, when a lone scout hit his 'Mech Bay. The only reason he survived was that he was tinkering around in a Centurion's custom-made rumble seat at the time and the armor took most of the damage. He lost two of his favorite assistants, his right arm, and got a cybernetic replacement as consolation.
It's one of many things he carried out of Capellan space and one he resents the most. He left the Confederates when his tour was over and never looked back. The greatest factor was the elitism saturating Capellan culture, and especially how it rewards highborn idiots at the common people's expense. As a result, he's naturally wary of nobles - your MechCommander excepted, for their skill in getting their hands dirty.