Rear Admiral Albert "Al" Calavicci

Al is Sam's best friend and only contact to present time once Sam gets stranded in the past. Al appears to Sam as a hologram and only Sam can see him as such (and apparently children, because they are still pure of soul). Al constantly has a handheld device through which he keeps contact with Ziggy, a supercomputer, that is tasked to ascertaining what Sam's task is before he could leap out of whatever body he is currently in. Al is also a war veteran, hence his rank, constantly carries a cuban cigar, and has been married so many times he keeps forgetting which wife he is referencing when comparing Sam's situation with his every now and then.