Jack Krauser was a former member of USSOCOM, serving alongside DSO agent Leon S. Kennedy in an anti-viral weapons mission to South America. Faking his death soon after, Krauser ended up working for Albert Wesker. His SOCOM codename was "Silverdax".
Jack Krauser was an experienced soldier within the United States Army, having led many successful operations. During his days off, Krauser often participated in mercenary work, as he felt that he cannot function within regular society and thus believed that combat situations and being in the military is what gave his life meaning.