Similarly, Iron Fist saw its recurring antagonist Davos survive the events of the series' second season and swear revenge on Danny Rand after his defeat at the hands of Colleen Wing. Having possessed the power of the Iron Fist himself over the course of Season 2, Davos certainly poses the great risk for both Danny and Colleen, as his imprisonment is virtually guaranteed to be temporary once he presumably regains his lethal chi-fueled abilities.
While Davos is currently locked away, Alice Eve's Typhoid Mary is still on the loose and teasing the presence of an additional, more violent alternate personality. The villain is perfectly primed to be recruited into a team of villains, having already proved herself more than a match for Danny.
While not technically a member of the Defenders, Jon Bernthal's Punisher exists within the same shared universe, having made his debut during the second season of Daredevil before receiving his own spinoff series. The show's principal antagonist is Frank Castle's old war buddy Billy Russo, who became the disfigured Jigsaw in the climax of the first season finale. Having served alongside Castle for years, Jigsaw knows the Punisher better than anyone else and held his own in brawls and gunfights with the no-nonsense crimefighter. Provided the character survives his rematch with Castle in the upcoming second season, he would make a killer addition to our potential street-level ensemble of villains.
And that leaves Netflix's Jessica Jones. The problematic thing about the Krysten Ritter-starring series is that it has consistently killed off its main antagonists in both of its first two seasons; David Tennant's Killgrave died at the hands of Jessica herself, while her villainous mother was shot to death by former best friend Trish Walker. But perhaps Jessica wouldn't bring off a recurring villain or a newcomer to the fold, but rather Trish herself. Over the course of Jessica Jones' second season, the two best friends had a massive falling out as Trish gained her own superpowers before the friendship completely ruptured after Trish killed Jessica's mother in a desperate bid to save her friend. With the ties that bind cutting the deepest, the two old friends are likely to be on an emotional collision course in their near-future, so why not see it happen on the biggest possible stage in Defenders' second season?
Marvel Television has been relatively non-committal about the possibility of the Defenders reteaming for another go around, a situation largely believed to exist due to the extensive behind-the-scenes logistics of such an undertaking. But with whole myriad of returning antagonists with a common goal and thirst for revenge against the street-level Marvel heroes, the various Netflix series could have the perfect new unifying premise for a crossover series to eventually happen after all.