Sixth Ranger Traitors in Live-Action TV series.
- Buffy the Vampire Slayer:
- In "Lie to Me", Buffy's old friend Ford transfers to Sunnydale High. He turns out to already know about vampires and Buffy immediately welcomes him into the Scoobies. It later transpires that Ford is dying, and is planning on selling out Buffy to Spike in order to become a vampire himself. He does not survive the episode.
- In season 3, Faith is introduced as a second Slayer and hedonistic Shadow Archetype to Buffy. It takes a few episodes, but a fatal accident sets her on a spiral into a Face–Heel Turn. She eventually makes a Heel–Face Turn and goes back to being one of Buffy's most important allies, though.
- Rather amusingly, Spike (who now has a Restraining Bolt to keep him from killing people) plays the Sixth Ranger Traitor role in season 4 — selling out Buffy and the Scoobies to Adam — despite the fact that he makes no bones about being evil and hating the Scoobies the whole time.Spike: Tell you what I'll do then. I'll head out, find this girl, tell her exactly where all of you are, and then watch as she kills you.*shocked silence from Xander and Giles*Spike: Can't any one of your damn little Scooby club at least try to remember that I hate you all? Just because I can't do the damage myself doesn't stop me from aiming a loose cannon your way. And here I thought the evening'd be dull.
- Oddly enough, the reality show Dance Moms has an example of this, when the newest mother to the group, Cathy, defects back to her own dance studio, then decides to directly compete against her erstwhile colleagues in an upcoming competition. She even specifically states that now she's seen the Abbey Lee company from the inside, so she can use their own methods against them, going so far as to steal one of the children's music. Like most Sixth Ranger Traitors, she fails spectacularly.
- Zig-Zagged in a third season episode of '"Homicide: Life on the Street''. Russert's old partner Doug Jones joins the unit and proves quite competent at the job. He never actually betrays the unit, but Russert discovers Jones is a brutal domestic abuser who feels no remorse about what he's put his wife through. The episode ends with his wife shooting him dead in self-defense.
- Zoey from How I Met Your Mother became one of these, after she grew very close with the gang and even dated Ted. However when Ted said "no" to preserving an old building called the Arcadian, said person revealed to have kept the recording she made of Ted praising the Arcadian despite having promised to get rid of it.
- Chester Lake from Law & Order: Special Victims Unit eventually ends up killing a rapist cop who was found not guilty at trial. To Lake's credit, said cop had previously tried repeatedly to kill him, and in the end he made no attempt to conceal his crime. Much more fitting to the trope is The Scrappy Dale Stuckey, who turns out to have masterminded a plot to kill the lawyers and judge in a serial killer's murder trial in order to frame the killer, who he had originally accidentally set free due to screwing up the forensic evidence. He ends up killing the Mauve Shirt CSU tech, and almost ends up killing Stabler.
- Rick Murray from Degrassi: The Next Generation. Crazy, check. Ready to explode, check. Attacks his friends, check.
- NCIS had both Chip, who inserted himself into NCIS as part of a long term scheme to get revenge on Tony for ruining his career years ago, and Agent Lee, who was an enemy double agent. For a while the team took it for granted that Ziva was one of these, being a double agent for the Israelis, but she eventually proves her loyalty to the team.
- Power Rangers and Super Sentai:
- Zhane in Power Rangers in Space actually disguised himself as a "Sixth Psycho Ranger" in order to confuse The Psycho Rangers.
- To the point, despite the trope name, this really hasn't happened in Power Rangers. Sixth Rangers have started as antagonists and even villains, but it's always been due to mind control or the manipulation of the truth. The closest examples would be Power Rangers Ninja Steel, where Brady's brother Aiden turns out to be Actually a Doombot sent by The Starscream, and the Mighty Morphin' Power Rangers comic which introduced an actual "Sixth Psycho Ranger" called Psycho Green who is later revealed in the Year Two Deluxe Edition to be the former Sixth Ranger of the Supersonic Rangers of Xybria who, after being benched too many times by his leader, lured the core Five-Man Band into a trap and killed them all. An act of betrayal that won over the favor of Dark Specter.
- One of the few examples of this happened in Choudenshi Bioman in a two part story where a man tries to join the team and fights beside them but gets rejected when the test for bio particles comes back negative. The villains take advantage of him by tricking him into letting them turn him into an evil ranger whose suit is powered by magne metal instead. Unlike future sixths rangers he does not keep his powers after he is freed.
- Revenge: If you go by Alternative Character Interpretation, Ashley Davenport, although she also isn't fully aware of her role in Emily's scheming and is at least partially loyal to the Graysons.
- The Torchwood episode "Adam" had the eponymous mind-altering alien acting as the team's most trusted member. The viewers know he's the bad guy all along.
