Supergirl David Harewood on How the J'Onn J'Onzz Revelation Has Changed Everything

Tonight, Supergirl introduces a White Martian -- a member of the race responsible for the downfall of Martian society and so, logically, a mortal foe of J'Onn J'Onzz, the last surviving Green Martian and, as Hank Henshaw, the director of the Department of Extranormal Operations.

It will give David Harewood, who plays Henshaw/J'Onzz, to shed his tough guy facade a bit and play with emotions that he hasn't had the opportunity to tap into yet on the series.

ComicBook.com spoke with Harewood about tonight's episode, what's next for his character -- and revealed a surprising piece of DC trivia that Harewood knew about J'Onn's past.

How is your portrayal of the character different now that it's been revealed that he's J'Onn J'Onzz?

It's been a lot of fun. I knew I had to keep a very tight ship in the early days, so it's nice that finally Hank is beginning to open up and feel all these different levels; it's a lot of fun to play.

Certainly you couldn't do this week's episode -- with White Martians -- and play your performance the same way if we didn't know the secret.

Yes, indeed. The White Martians are responsible for the complete destruction of the Green Martians, of his race.

We purposely set out to make it look pretty graphic and pretty brutal, very much along the lines of how we humans do genocide. It was very emotional for a lot of us, because you're going to get to see just how cruel we can be to each other. Even though it's a comic book show and it's aliens, it's never pleasant to see a parent ripped away from their children's hands. It's pretty emotional stuff.

After he's ripped from his child's hands, do we see how J'Onn ended up coming to Earth?

We don't actually touch upon that, that's one of the things we haven't touched upon. We just presume that he's been here for over 300 years, so we do mention that, but we don't actually talk about his arrival on Earth.

What about filling in some of the blanks from your time on Earth? Do you think you could get your own episode down the line, or maybe in a prospective Season Two, to explore some of that mythology?

We do touch upon that. We do see some wonderful flashback moments that explain a little bit of Season One.

Obviously it's not my show, so I'm not necessarily holding a candle out for [an episode] -- but he's got such a rich backstory, such a wonderful mythology that it would feel a shame not to use that as a way to tell the many stories he's been through.

One of the things I'm most delighted about is getting to know the show creators, and that they're all huge fans of these characters so they are treating them with the utmost respect. Luckily for me they're huge Manhunter fans.

Any chance we'll see him interacting with the Justice Experience? After all, we saw Cameron Chase last week. Do you know who the Justice Experience even are, I guess I should ask?

I do remember that. There was a superhero team that he shapeshifted into being another hero, right?

Right.

But where did you think you saw Cameron Chase?

In last week's episode, the FBI agent who tried to shoot Winn identified herself as Chase.

Oh! I missed that. That's very good; that's interesting.

Are we going to explore J'Onn's powers a little? Obviously at some point he had enough control of his mental powers to convince people who presumably knew Hank Henshaw, that he was the genuine article -- and yet when we see him try to mind-wipe that guard, it went pretty badly.

I think he's spent so much time as Hank that he's almost forgotten the range and effect of his powers. I think what we're learning, just as Kara learns over the course of the first seven episodes, she learns to control her powers and gets to know them and gets to know how to use her anger properly like she did brilliantly in the Red Tornado episode.

Hank hasn't used his Martian powers in many years, so I think it's interesting to see him get better at it. There's definitely times in the next couple of episodes where he's not as afraid to use his powers as he was in that episode. I think definitely we are seeing Hank regain full measure of his powers. I think by the end of the season he'll be much more familiar with Martian Manhunter than at the beginning of Season One.

There are basically two big things that we get from White Martians: We get the invasion storyline where they were posing as ordinary people to set up an attack, and you get one White Martian who would become a heroine. Do you think they're setting up for either of those stories here, or is this more just an opportunity to explore J'Onn's past?

I think again we do explore the fact that [White Martians] were undercover and toiling underground. What's so clever about this show is that they take established DC lore and keep its essence but tell it in a different way.

I think we'll see both of those played out in this episode, but in an original and clever way that works for television. But it's still very much DC lore.