Fascinated by mechanics, explosives, and all things dangerous. He likes to figure out how stuff works by taking it apart and seeing what makes it tick; oftentimes this gets him into trouble when he dismantles something he shouldn't have. Or it blows up in his face.
Mull is almost guaranteed to have bandages or a cast somewhere due to his insatiable curiosity, but he is always in good spirits and ready to explore the next hazardous thing that comes along. Despite this reckless tendency to tinker and naivety to the danger it poses, he is a friendly, amiable character. Understandably, others still prefer to give him a wide berth... smelling like soot and burnt copper probably doesn't help either.