Cyrus grew up in a post-war semi-tribal farming community (hence the tattoos). This community had its share of problems with raiders, radscorpions, and the like, but was finally devastated by the super mutant army when he was just a boy. So, like a lot of adrift-in-the-wilderness youths, he wandered briefly, avoiding radscorpions and raiders, hearing stories about the defeat of the mutant army and the forces that opposed them. It was inevitable that Cyrus would eventually go to join the Brotherhood of Steel, hoping to save the lives and dreams of boys who are like he once was. Impressed with his huge physical form and determination, the Brotherhood sent Cyrus on an Initiation quest. As a soldier, Cyrus is a strange combination of idealist and bad-ass. In short, he is the modern-day post-apocalyptic knight.
Has the ability to use very big guns to fight with
He maneuvers better than the other characters with heavy weapons
He isn't able to run while firing weapons; instead he slows to a walk