Last fall, Supergirl debuted on CBS and introduced a new corner of the DC Comics television universe - this time inhabited by Kara Danvers (Melissa Benoist), the last daughter of Krypton. Throughout its first season, Supergirl followed Kara as she faced villains and saved the world with the help of her friends and family, including her adoptive sister Alex Danvers (Chyler Leigh), Winn Schott (Jeremy Jordan), Jimmy Olsen (Mehcad Brooks). Kara also worked alongside head of the DEO, Hank Henshaw (David Harewood) - who revealed himself to be fellow extraterrestrial J'onn J'onzz a.k.a. Martian Manhunter.
Season 1 depicted J'onn's origin story, in which his family was wiped out along with the rest of the Green Martians by the violent White Martians. He believed himself to be the sole remaining Martian and arrived on Earth a refugee, where he lived hidden among humans until he met Kara. However, season 2 will introduce a new Martian in the form of M'gann M'orzz a.k.a. Miss Martian (Sharon Leal) and her arrival will force J'onn to confront his past.
Speaking to EW, Supergirl executive producer Andrew Kreisberg explained how Miss Martian will factor into season 2 of the series, and how her appearance will bring J'onn's grief to the forefront. Kreisberg said:
J’onn is suddenly going to have this connection to Mars that he’s been lacking for the last 300 years. He’s dealing with survivor’s guilt, and he’s spent the last few hundred years burying that. It’s only because of his interactions with Kara and his deepening relationship with Alex that he gets to start to tap back into that. The arrival of Miss Martian is really going to open the floodgates.
In the comics, M'gann is a White Martian though she looks like (and pretends to be) a Green Martian. It's unclear whether Supergirl will maintain this aspect of her character. However, the series has so far stayed true to Martian Manhunter's origin story and it would certainly provide for compelling drama if Miss Martian were to reveal herself to be a White Martian given the backstory between J'onn and the race of Martians that was portrayed in season 1.
It was previously teased by Harewood himself that, since the show has moved to The CW, Supergirl season 2 will include more Martian Manhunter - specifically, he said, more "alien superhero stuff." It would appear Miss Martian is one character that will be part of Supergirl's expanding roster of alien superheroes in season 2, though she won't be the only extraterrestrial addition. Supergirl season 2 will also introduce Mon-El (Chris Wood), a Daxamite alien - a race very similar to Kryptonians - as well as Kara's superpowered cousin Clark Kent a.k.a. Superman (Tyler Hoechlin).
These superpowered extraterrestrial characters will join fellow new additions: NCPD detective Maggie Sawyer (Floriana Lima), Kara's new boss Snapper Carr (Ian Gomez), and Lex Luthor's sister Lena (Katie McGrath). All in all, season 2 of Supergirl will feature plenty of new faces - and less of season 1 standout Cat Grant (Calista Flockhart) - as the show continues to explore Kara's life as both a CatCo employee and the Girl of Steel. But, it remains to be seen how well these new characters will fit into the expanding world of Supergirl.
The Flash season 3 will premiere Tuesday, October 4th at 8pm on The CW, Arrow season 5 will premiere in the same time slot on Wednesday, October 5th, Supergirl season 2 on Monday, October 10th, and Legends of Tomorrow season 2 on Thursday, October 13th.