Works for Tazeroth
When he was young Leo was fascinated with machines and explosives. He was good friends with Arnan and they grew up learning new stuff together until Arnan went underground. After a few years he met up with Loradel and they both found that they liked explosives so they became friends. They always thought odd things like magic and machines were cool so eventually they began working for Tazeroth and helping him hunt down magical items.