Brimstone is an agent who's the oldest of the group and a commander with a long history of wearing an uniform, but as of teaching from age and experience wasn't enough to prove his place in leading an organization composed of unique individuals who are each an elite in their own right, then perhaps continuing to work with boots on the ground sealed the deal.

Note : The VA is Steve Blum. If anyone can do Steve Blum's deep voice, you're welcome to audition.