After an explosive winter finale, “Shadowhunters” has left us withe one huge question: Who the heck has that Soul Sword, and what do they plan to do with it?

While Clary (Katherine McNamara) and Jace (Dominic Sherwood) planned an assault with the Downworlders from outside the Institute, it was up to Alec (Matthew Daddario) and Aldertree (Nick Sagar) to mount an attack from the inside. Naturally, neither of their plans worked as planned, and the Soul Sword was officially activated — and then immediately stolen by a mysterious hooded figure.

We’ve got a few guesses about who’s under that hood, and we took our guesses to Matthew Daddario. He’s keeping mum about this mysterious new character, but we did manage to get him to spill about that swoon-worthy “I love you” between Alec and Magnus (Harry Shum Jr.).

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Obviously, the question on everyone’s minds is who stole the Soul Sword. What can you tell us about that?

The Mortal Instruments are being handed around left and right, and you don’t know who’s got ’em and then you do know who’s got ’em. It’s a mess. The Soul Sword obviously has a little too much power. That’s not good. We know what it does to people with demonic blood, and that’s quite scary. There might be a new character who’s seeking it out, we might have some people at the Clave who are not being truthful about things, and we might have Valentine hatching a new plan that he hasn’t made us privy to.

It’s nice that it’s all very open-ended because we don’t really know who the good guys and bad guys are. It seems to change a lot. In the second half of the season, we’re going to see that the line is kind of blurred between who’s good and who’s bad.

Can we assume there’s going to be even more tension now between the Downworld and the Clave after this latest massacre?

The big issue is obviously going to be, if you’re a Downworlder, how are you going to trust these policing Shadowhunters, who are just leading to the death of your own people? It’s not easy to say that their anger is not justified. I think that a lot of what we’re going to see is this political issue with the Downworld, and how they respond to the Shadowhunters’ relative incompetence, and this ongoing annoying element of Valentine.

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You’ll definitely see the Shadowhunters try to deal with that. We’re going to see some power struggles.

Where is Malec headed after that super sweet “I love you” moment?

I think that the big thing — and it always is with the Magnus and Alec relationship — is keeping things honest, and enjoyable for the fans. At this point now we get to say “Okay, they’re a couple — and although it’s been very quick, they’ve discovered that this is a healthy and nice and sweet relationship, and they can rely on each other for things going into the future.”

Things aren’t always perfect in relationships — but we’ll see a lot of goodness between the two of them, and the relationship grows stronger over the course of the second half of the season.

Emeraude Toubia Matthew Daddario 'Shadowhunters'

Will Aldertree’s story about his own past romance with a Downworlder affect how Alec sees his relationship with Magnus?

I don’t know! You know, Alec is still stubborn — even though he’s a little less stubborn — and I think that he’s not very inclined to listen to Aldertree, who has proven himself to be a bit of a snake. Although he’s a redeemable character, in Alec’s eyes, he’s still got his sister addicted to yin fen, and was not very honest with his motivations and with his actions.

I think although it’s a nice thing to see Aldertree’s humanity, at the same time I think Alec sort of takes it with a grain of salt. I’m sure he’s considered those [possibilities]. What do you think?

I think Shadowhunters and Downworlders can make it work! I think Magnus and Alec can make it work!

Of course they can make it work! They’re all just people — some of them just have a little demon blood in them. So what?

Speaking of demon blood, Jace has just found out he doesn’t have demon blood, and he’s not even Valentine’s son.

Alec is obviously dying to tell Clary — No, I’m just kidding. I think he wants to see what’s best for his brother — but at the same time it’s like this little mess that we have going on… There are some bigger things going on. Jace sort of says, “You know what, she’s happy in this situation. I’m going to let it go, and then hopefully at some point in the future I’ll deal with it.”

I guess it’s just putting things off, which is a common problem people have. Putting off telling people things that will cause momentary struggle because they’re afraid of what the response will be.

Alec won’t meddle. Alec won’t meddle much in this situation, although he does find it amusing in a kind of twisted way. I don’t feel like Alec is a meddler, he’s kind of a straight shooter — and I feel like if he does meddle in something it will be very, very sneaky.

What can you tell us about this Sebastien character we have yet to meet?

I can tell you that Will Tudor is a great actor that’s playing a complex character — who comes in, and we don’t really know a lot about him. Here’s this fancy British guy coming in, talking all sweet to everybody, but you don’t really know what he’s doing. I think that it’s definitely going to start to become clear by the end of the second half, but you’re going to have to keep your eye on him…

“Shadowhunters” airs Mondays at 8 p.m. ET/PT on Freeform.

Posted by:Lindsay MacDonald

Lindsay MacDonald is a Los Angeles based entertainment reporter with an affinity for CW superheroes. She graduated from Pepperdine University with a major in Media Studies and a borderline unhealthy obsession with TV in 2012. She would much rather spend the day binge-watching ‘The Flash’ or sorting ‘Game of Thrones’ characters into Hogwarts houses than venturing outdoors. TV words to live by: “Never ignore coincidence. Unless, of course, you’re busy. In which case, always ignore coincidence.”