Fox Mulder (The X-Files). When he was twelve his sister was abducted -- by aliens, he came to believe. He entered the FBI and opened the X-Files division to investigate UFOs, hoping to find her, but what he found was a shadow government possibly working in collaboration with an invading alien force.
Dana Scully (The X-Files). She's Fox Mulder's partner and best friend, and the scientific half of the X-Files division. Even Mulder rarely messes with her.
The Cigarette-Smoking Man (The X-Files). A key player in the shadow consortium, the only things reliably known about him are that he rarely acts without a plan and that he prefers to smoke Morley cigarettes.
Alex Krycek (The X-Files). He seems to be a mere errand boy for the consortium, but somehow he's always in the right place at the right time. Mulder trusted him once, but he became a suspect in several consortium-orchestrated crimes, including the assassination of Mulder's father, and now Mulder hates him with a passion.
James Ellison (The Sentinel). As an army covert operative, he led a disastrous mission into Peru that left him stranded in the jungle for eighteen months and forced him to develop his senses to an incredible level. Five years after resigning and becoming a police detective, he found his so-called "Sentinel" senses returning, this time almost under his control.
Blair Sandburg (The Sentinel). An anthropologist who studied legendary Sentinels until the day he met Jim Ellison, he finagled himself a place as Ellison's partner because he, as a Shaman and Guide, was the only one who could help the Sentinel gain control of his abilities.
Cascade, Washington (The Sentinel). This fictional city in Washington State is home to Ellison, Sandburg, and Rainier University, where Sandburg is working on his PhD.
Other X-Files characters include Walter Skinner, Assistant Director in the FBI and Mulder and Scully's direct superior, and three computer gurus (Byers, Langly, and Frohike) known collectively as the Lone Gunmen.
Other Sentinel characters include Simon Banks, Captain of the Major Crimes department where Ellison and Sandburg work; their co-workers Captain Joel Taggart (of the Bomb Squad), Detective Henri Brown (called "H"), Detective Rafe (first name unknown), and Inspector Megan Conner (the Australian); and Sandburg's mother Naomi.
All X-Files characters are copyright Chris Carter, Ten-Thirteen Productions, and Fox, and are used without permission. All Sentinel characters and locations are copyright Pet Fly and UPN, and are used without permission.