History AscendedExtra / LiveActionTV

** Darla was initially just a random female vampire in the pilot but Julie Benz put enough into the character to keep her around and make her Angel's sire. Even then [[spoiler: she died in the episode that that fact was revealed in...only to be resurrected by Wolfram & Hart at the end of the first season of ''Angel'' and becoming a major figure in that show's story.]]

* ''Series/ThePolkaDotDoor'': Initially, Polkaroo only appeared on Imagination Day, but as the character became popular with fans, he started to appear outside of Imagination Day. After the show ended, TVO capitalized on Polkaroo's success by turning him into a [[Main/BreakoutCharacter]].

* ''Series/ThePolkaDotDoor'': Initially, Polkaroo only appeared on Imagination Day, but as the character became popular with fans, he started to appear outside of Imagination Day. After the show ended, [[Main/BreakoutCharacter he became the main protagonist of Polka Dot Shorts]]

* Most of the characters in ''Series/AgentsOfSHIELD'', by necessity. Because almost any character with any real prominence in the comics has been earmarked for use in the [[Franchise/MarvelCinematicUniverse MCU]] films or Creator/{{Netflix}} shows, AOS largely has to deal with obscure barrel-scrapers who never got much page time in the comics. For instance, despite only ever appearing in just over a dozen or so comic issues before the show, Lance Hunter is one of the main characters.

* ''Franchise/{{Arrowverse}}'':
** Felicity Smoak may well be the crowning example. She started as a one-scene character in ''Series/{{Arrow}}'', never intended to return, but her portrayal by Creator/EmilyBettRickards was well-received by both the creators and the audience and she was promoted to a recurring role in early-mid season 1. By season 2, she was a main character, and coming into season 3 was essentially the ''female lead'' of the show.
** Sara Lance was originally just a backstory, PosthumousCharacter in the first season of ''Arrow'', only appearing in the flesh in the pilot with all others being archive footage. Come the second season's first episode and it's revealed that Sara is not only still alive, but being the first incarnation of the ComicBook/BlackCanary, the ComicBook/GreenArrow's traditional female partner in the comics (though she insists it's just "The Canary"). Sara later transfers to the ''Series/LegendsOfTomorrow'' where she becomes by far the most prominent member, one of the only three to remain to this day. Also a case of ThePeteBest because the stark difference between Sara's importance pre- and post-''Arrow'' season 2 is also accompanied by a recast (Sara is portrayed by Jacqueline [=MacInnes=] Wood in the pilot and Creator/CaityLotz afterwards).
** ''Legends of Tomorrow'' in general stars many of the B-list superheroes and supervillains from its predecessors, but the one that stands out is Mick Rory. While Sara was retooled as a major character in ''Arrow'' season 2 before her {{Transplant}}, Mick was just one of the myriad [[MonsterOfTheWeek villains of the week]] that Team Flash encountered and only appeared twice in ''Series/{{The Flash|2014}}'' before his transfer. Ultimately, he is one of the aforementioned three original members still on board the Waverider, outlasting both his partner, the EnsembleDarkhorse Leonard Snart, and the show's original male lead, Rip Hunter, both of whom departed from the show after the third season.

* Sophie in ''Series/{{Batwoman|2019}}'' is a main member of the supporting cast, both as the second-in-command of the Crows and as someone Kate still has feelings for. Her comics counterpart had the same role in Kate's ComingOutStory, and has otherwise made a single non-flashback appearance.

* ''Series/LukeCage2016'':
** While Mariah Dillard is among the main villains of season 1 and in 10 of 13 episodes, she's always forced to play second-fiddle to the main villains of Cottonmouth and Diamondback. In season 2, she is the main villain overall front and center, and the season is about her trying to stay on top as others like Luke, Misty and Bushmaster try to bring her down for various reasons. The same is true of Shades, who also gets more focus in season 2.
** Shades' cellmate / [[spoiler:prison lover]] Darius "Comanche" Jones only appears in a flashback episode of season 1 about Luke's time as a prisoner at Seagate. In season 2, he has a much more prominent role.
** Sugar, an enforcer for the Stokes' and later Mariah's driver, has a more prominent presence in season 2 compared to season 1.
** D.W. Griffifth only gets a few scenes in the first season, first being seen peddling HD footage of the Incident to Harlem passerby outside Pop's, and later being used by Luke to get information on Domingo Colon's base of operations. In season 2, he's a more prominent fixture, having become Luke's videographer and now selling Luke Cage-branded merchandise out of Pop's Barbershop.

* Series/Peacemaker2022: Harcourt and Economos were both minor side characters in ''Film/TheSuicideSquad'' who become full members of the main cast of this series.