The Defenders finally saw the four protectors of New York City - Matt Murdock, Jessica Jones, Luke Cage, and Danny Rand - team up to take on the Hand, but showrunner Marco Ramirez has said however that it's unlikely that these four characters will team up again. A second season of The Defenders has not yet been officially announced by Netflix, but if the band isn't getting back together, could a second season feature a different lineup of Defenders? In the comics, The Defenders had a rotating membership that included characters like Namor the Sub-Mariner, Bruce Banner, Doctor Strange, Valkyrie, Falcon and even the mutant Polaris (who will appear in Fox's The Gifted.)
The Defenders never specifically called themselves Defenders, or unified themselves beyond being driven by the actions around them. They aren't The Avengers after all, and they've done well so far without a leader. A second season of The Defenders doesn't have to feature the original line up at all, and could be a good chance to spotlight some new characters, as well as develop some of the side characters and Easter eggs that the show has left in the streets of Hell's Kitchen. Folks who watched The Defenders noted that the series could have set up a potential Daughters of the Dragon spin-off, as well as leaving some threads that could be turned into the Luke Cage and Danny Rand vehicle Heroes For Hire.
It's those threads that make one wonder if a second "roster" of defenders is feasible. Colleen Wing and Misty Knight deserve to headline their own show, and if season 2 of Iron Fist might lead to a potential second season of The Defenders that could be a good opportunity for Colleen and Misty to step off to adventure. Alternatively, developing a Daughters of the Dragon spin-off could also lead into a second season of The Defenders if they chose to develop that first. Both women are focused on doing good and could be brought into a mystery that might require a second collection of super powered individuals.
If a second season of The Defenders happens, then Claire Temple needs definitely needs to be a part of it. She's taking self-defense classes with Colleen Wing and she's currently in a relationship with Luke Cage - plus, she seems to be a magnet for people with superpowers. And since every team needs a wild card, it might be interesting to include Frank Castle. The Punisher series debuts in 2017 and will see Frank Castle and Karen Page take on villains in Hell's Kitchen.
Another potential addition to the line-up is Trish Walker (also known as Hellcat in the comics) who, unlike Claire Temple, has a hunger to acquire superpowers and use them to save the world. Having been raised with Jessica Jones her whole life, she's seen Jessica's abilities first-hand. Her investigations of Jessica's past have put her in connection with her mother, as well as put her on the path of the people who gave Nuke, Jessica, and Kilgrave their abilities. Trish could serve as a member of The Defenders, or even as a potential villain. In the comics she fell in love with Damion Hellstrom, also known as the Son of Satan, and when he lost his battle with his demonic side she went mad at the sight of him. She ended up in Hell after killing herself and was brainwashed into being an enemy of the Avengers and the Defenders, who eventually got through to her and helped free her from the magical influence.
There's precedent for Trish Walker to have a dark side in Jessica Jones. After she tries Nuke's "super pills" she briefly loses control and tries to hurt him. If she had an opportunity for power, is there a chance that the person who wants so desperately to be a hero could turn into a villain before becoming an anti-hero like her best friend Jessica? Whatever path they decide to give to Trish as either a hero in her own right or as a potential villain, she should feature in the second season of The Defenders.
One final option is the Jessica Jones Easter egg that mentioned another new potential Defenders hero - Angela Del Toro also known as White Tiger. In the comics, Del Toro is an FBI agent who wears a magical tiger amulet to gain superpowers. In the MCU Jessica calls her another private investigator with reasonable rates, but discovering Del Toro's story in, say, a Daughters of the Dragon spin off could lead to White Tiger joining the Defenders. Just as Frank Castle was spun off into his own series after Daredevil season 2, there are plenty of New York heroes who could make a splash in any future Netflix properties. Del Toro, however, was mentioned by name and she should be one of the first in line for development.
The potential for a crossover from other Marvel Television series like Agents of SHIELD might be difficult, but there are plenty of characters in New York city who deserve the chance to defend it. If Matt Murdock and the rest of the original team is unavailable, it might be time for some other characters to step in. Thankfully, from Colleen Wing and Misty Knight to the idea of Angela Del Toro, there are plenty of heroes ready to step into the ring and defend their city.