Supergirl season 2 has seen a number of changes thanks to the show shifting from CBS to The CW, as well as some that are simply a result of the show growing in its sophomore outing. Supergirl has most recently focused on CADMUS, the arrival of Mon-El (Chris Wood), and Alex Danvers' (Chyler Leigh) coming out to her friends and family. But, with CADMUS now seemingly defeated in the fall finale of Supergirl, it remains to be seen who the Girl of Steel will face off against in the second half of season 2.

Well, a few familiar faces are returning to Supergirl, and if their past behavior is any indication, they're going to be causing a few problems in National City.

According to TVLine, both Livewire and Metallo are set to return to Supergirl in 2017. Metallo, aka John Corben (Frederick Schmidt) previously appeared in the first two episodes of the second season, "The Adventures of Supergirl" and "The Last Children of Krypton". Initially a normal human, Corben was captured by CADMUS, an anti-alien organization bent on destroying Supergirl. He was experimented on, turning him into the superpowered cyborg known as Metallo. Since Metallo gets his powers from Kryptonite, he was more than a match for both Supergirl and Superman. But, they eventually managed to stop him, as well as a second cyborg, with help from their friends.

Livewire, aka Leslie Willis (Brit Morgan) was one of the show's first villains, introduced in the fourth episode of the series, aptly titled "Livewire". A protege of Cat Grant, Leslie developed electricity-based powers after being struck by lightning. She targeted Cat, who she blamed for the lightning strike, and after being stopped by Supergirl, was imprisoned at the DEO. She made a second appearance later in the first season during "Worlds Finest", a crossover with The Flash. This time, Livewire teamed up with Silver Banshee, and they again went after Cat Grant, as well as Supergirl.

Both returns are potentially earth shattering. Livewire constantly targeted Cat Grant, who has not been seen since "The Last Children of Krypton". Considering the reappearance of Livewire, and the recent report that Calista Flockhart may reprise the role of Cat Grant again in season 2, their respective returns may coincide. Or, it's possible Livewire has found a new target, perhaps something to do with her former ally Silver Banshee, who may return as well.  Executive producer Ali Adler also told TVLine that other "fan-favorite" villains will be returning. So perhaps Livewire is only the tip of the iceberg.

As for Metallo, he was dead the last time we saw him, or at least he appeared to be. Perhaps, being a cyborg, he simply "shut down" and is able to "turn on" again. Or, maybe Cadmus has the ability to bring him back somehow, making them an even bigger threat than they have already proven to be.

Any other fan-favorite villains you're interested in seeing return? Or theories about these two returning foes? Let us know in the comments.

Supergirl season 2 continues with ‘Supergirl Lives’ Monday January 23rd @8pm on The CW.

Source: TVLine