Jim Castillian is a flamboyant, charismatic OSI agent — part of the "new guard" at the OSI, since Steve Austin's and Jaime Sommer's departure. When he introduces himself, he insists everyone understands his last name is spelled with two "L"s. Despite his bravado, Castillian is actually competent and the best field agent the OSI has to offer, at the time his character is introduced in the Return of the Six Million Dollar Man and the Bionic Woman reunion movie.