Adding new characters to a long-running television show is no easy task. In fact, there’s an entire trope called the Cousin Oliver, named after the character from the 1970’s classic The Brady Bunch. This is an extensive list of TV characters that were created late in the game to “spice things up.” This trope usually has a negative connotation, but not all late-stage characters are denounced by fans. For every Scrappy-Doo, there’s a gem that goes on to become a fan and critics darling.
Let’s look at ten fan-favorite TV characters who weren’t a part of the show’s original cast. But be warned, there are a few spoilers as well.
10 Frank Reynolds: It’s Always Sunny in Philadelphia
The hit FX show It’s Always Sunny in Philadelphia is one of the longest-running comedies on television. As of 2022, it has 15 seasons under its belt, with no sign of slowing. Considering its humble beginnings, it’s easy to call this the little show that could. In the early 2000s, Charlie Day, Glenn Howerton, and Rob McElhenney were aspiring actors who crossed paths while auditioning for other films and TV shows. They eventually started shooting their own home movies on a Panasonic DVX100A, out of which the idea for It’s Always Sunny was born.
After shooting a pilot on a camcorder, it was picked up by the cable channel FX. The show was slow to attract an audience at first, but the execs at FX believed in it. They realized something was missing from the cast and decided to add a big name.
Enter Danny DeVito.
Despite the cast’s initial hesitation, Devito was added in season 2 as Dennis and Dee’s stepfather Frank Reynolds. The character is the polar opposite of the lovable persona DeVito is known for publicly. Instead, Frank is crass, profane, and cynical, making him the perfect addition to this dark comedy. This addition pulled the show back from the brink of cancellation. Most long-time fans of the show agree that DeVito’s character was the cherry on top that elevated a good show into greatness.
9 Ben Linus: Lost
For fans of the hit ABC show Lost, it’s almost hard to remember that Benjamin Linus was not part of the original cast. This serialized drama had audiences hooked from the get-go with its unfolding mysteries. Beyond its successful first season, the show only continued to grow in popularity with its sophomore outing. And much of that growth is thanks to the addition of actor Michael Emerson in the role of Ben.
For most of the second season, Ben was held prisoner and fooled the main group into thinking he was a man named Henry Gale. When his lies are unearthed at the end of the season, it’s revealed that Ben is actually the leader of The Others, a shadowy group that inhabits the unexplored side of the island. Worst of all, Ben spent most of season 2 exactly where he wanted to be—observing the group. Ben’s grey morality, thirst for power, and often murderous tendencies are just a few of the qualities that make him a fan favorite.
8 Fin Tutuola: Law & Order: Special Victims Unit
Much like Danny DeVito in It’s Always Sunny in Philadelphia, Ice-T was a well-known entertainer before joining the cast of Law & Order: Special Victims Unit at the beginning of its second season. In the show, he plays Odafin “Fin” Tutuola, a street-wise cop who transfers to the SVU from narcotics. His character has a tough exterior but a passion for helping abused children and victims of rape and assault. He is initially paired with Munch, a cynical and jaded older detective with a penchant for conspiracy theories. Despite being polar opposites on the surface, many SVU fans felt these two characters had a chemistry that matched that of Benson and Stabler, the show’s leads at the time.
Currently, Fin has been a main character on SVU for 22 years, making him the longest-tenured non-orignial castmember on this list. After Elliot Stabler left the squad back in 2011, Fin became the now-Captain Benson’s right-hand man and longest-running supporter.
7 Rafael Barba: Law & Order: Special Victims Unit
The role of the assistant district attorney on Law & Order: Special Victim Unit has long been a revolving door. It’s tough to say which has been the most popular with fans, considering how loved Alexandra Cabot and Casey Novak were, but Rafael Barba easily gave them a run for their money.
Barba, played by Broadway vet Raul Esparza, first appeared in the season 14 episode “Twenty-Five Acts,” making him the latest season-joining character on this list. The actor was bumped up to a series regular the following season. Barba was known for being a no-nonsense strategic thinker who looked sharp in a three-piece suit. Fans of the show quickly embraced him for his wit, sass, and charisma. His character was the first male ADA to join the main cast.
In 2018, Esparza decided to leave the show and revive his stage career. His character received a rather divisive send-off in the episode “The Undiscovered Country” but has since made guest starring appearances across the 21st through 23rd seasons.
6 Desmond Hume: Lost
Desmond Hume is one of the most enigmatic characters to come out of the show Lost, and that’s saying a lot. His first scene alone is considered one of the show’s most iconic when he is revealed to be among the contents of the hatch, one of the central mysteries of the show’s first season. Despite appearing in the first scene of season 2, his character takes off and isn’t seen again until the season finale. Desmond becomes a regular cast member the following year.
At first, Desmond appears to have lost his sanity, which is unsurprising since he has spent years in solitary confinement, thinking the world outside the island no longer exists. But as the series progresses, we learn more about his backstory, and a beautiful love story between him and his wife Penelope unfolds. His character is the main focus of the much beloved season 4 episode, “The Constant.” This surreal episode ties “Through the Looking Glass” as the top rated of the entire series, according to fans on IMDB. Desmond’s story is quite different from the vast majority of characters on Lost, but that uniqueness, paired with his affable and kind nature, is what makes him a favorite.
5 Tommy Oliver aka the Green/White Ranger: Power Rangers
The first season of Mighty Morphin Power Rangers became a surprise smash hit with millennials back in the mid-1990s. Kids flocked to these five karate chopping, color-coded superhero teens. But the show shocked fans when it introduced an evil ranger in the 17th episode of the first season. Tommy Oliver was the new kid on the block, who also happened to be under the spell of Rita Repulsa, the arch nemesis of the show’s heroes.
What made Tommy popular with audiences was not just his long hair and bad boy looks—Power Rangers fans also empathized with his quest to find family and belonging. Beyond this, the show’s writers flexed their skills by crafting a great redemption arc in which he eventually regains control of his mind and goes on to lead the group as the White Ranger. The character also had an epic romance with Kimberly, the Pink Ranger.
4 Michonne: The Walking Dead
Michonne Hawthorne is one of the most popular, and most lethal, characters from the hit AMC show The Walking Dead. However, many long-time fans of TWD forget that this katana-wielding assassin was not part of the original cast—despite making a brief cameo as a cloaked figure at the end of season 2. However, she does not become a regular cast member until the following season.
In the beginning, Michonne travels with Andrea, one of the main characters from the first two seasons. But the two quickly part ways when Andrea decides to stay in the mysterious suburban community of Woodbury, which Michonne rightfully doesn’t trust. So she goes out on her own and happens to cross paths with Rick Grimes and the rest of Andrea’s original group of survivors. Despite initial hesitance to trust her, Michonne quickly befriends Rick’s son Carl and eventually ends up in a relationship with Rick himself.
Michonne, played by Black Panther star Danai Gurira, remained a main cast member on The Walking Dead until its 10th season. She is believed to have a kill count that rivals that of Rick Grimes and Daryl Dixon.
3 Lexa: The 100
There aren’t many characters on this list whose death almost tanked the entire show. The 100 is a post-apocalyptic teen series that aired on the CW from 2014 to 2020. The show focused on a group of 101 juvenile delinquents sent down to Earth from a space station 97 years after the end of the world. While never becoming a ratings juggernaut, the show maintained a fairly healthy viewership and garnered a passionate online fan base throughout its seven-year run.
In its second, and arguably best, season, The 100 introduced what would eventually become their most iconic character—a warrior queen named Lexa, played by Alycia Debnam-Carey. Lexa is introduced in a similar manner as Ben from Lost. The audience is led to believe she’s a limping servant girl, but it’s soon revealed that she is the leader of the grounders, the main antagonists (and eventual allies) of the first 2 seasons.
Lexa quickly became the love interest of Clarke, the show’s main character. In the third season, her character was killed by a stray bullet meant for Clarke soon after the two consummated their relationship. Off-screen, Debnam-Carey was simultaneously cast as a lead in the AMC series Fear the Walking Dead and was unable to continue shooting The 100. Unfortunately, many fans were furious and the show received a lot of public backlash. This also resulted in a drop in viewership and the show losing sponsors. Despite limping on for four more seasons, The 100 never quite regained its popularity.
2 Spike: Buffy the Vampire Slayer
Buffy the Vampire Slayer is easily one of the most critically acclaimed supernatural teen dramas to ever grace the airwaves. The show originally was conceived as a retooled version of a movie of the same name, both by writer and director Joss Whedon.
In the third episode of the second season, the hit WB show introduced a handsome, bleach-blond vampire named Spike, played by actor James Marsters. Spike is a fast-talking, charismatic bad boy who dons a leather jacket and rides in on a motorcycle. He is, in many ways, the antithesis of his old friend Angel, who is Buffy’s boyfriend and the only vampire with a soul. While Angel tries to live up to his name, Spike, on the other hand, revels in being bad.
Despite his edgy exterior, Spike is a hopeless romantic at heart who believes in the beauty of love and poetry. Spike also has a contentious and controversial romance arc with the lead character Buffy, which is something that continues to divide the fanbase decades later. The character not only spent six seasons on Buffy the Vampire Slayer, but he also spent time as a lead character on the spinoff show Angel.
1 Klaus Michaelson: The Vampire Diaries
Rounding out the list is yet another vampire—well, hybrid, to be correct. The Vampire Diaries quickly became must-see television for teens when it premiered back in 2009. And despite its successful and fast-paced first season, this CW outing massively upped its game in season two by centering the plot around a family of vampires called the Originals.
Klaus is essentially the patriarch of the Originals, who are the original family of vampires within TVD lore. This makes him different from your run-of-the-mill vampire. While most vampires in The Vampire Diaries universe can be killed with any wooden stake, original vampires can only be killed with a stake made of wood from an ancient tree. Klaus also becomes part-werewolf, making him the first hybrid in this cinematic universe.
Power and strength aren’t the only things that made Klaus such an unforgettable character. For one thing, he’s played by classically trained actor Joseph Morgan, who many say is one of the best actors to grace the CW. On top of being a dominant alpha, Klaus is a tortured artist who puts family before everything. His character became so popular that he was chosen to star in his own spinoff series, aptly titled The Originals.