'Shadowhunters' Exec Producer Explains Why 'The Mortal Instruments' Works Better as a TV Show

"What we learned was that just trying to compress this very big saga into an hour and a half was not the right approach," Ed Decter tells THR.
Courtesy of ABC

The question of whether Shadowhunters will stay true to Cassandra Clare's Mortal Instruments book series has been definitively answered: yes. 

The Freeform drama's series premiere only strays from its source material in subtle fashions — changing a character's age here or profession there. But the big picture storyline follows the YA book series like a road map, telling the beginning of Clary Fray's (Katherine McNamara) journey of training to become a Shadowhunter, a half-angel, half-human demon hunter.

After her mother Jocelyn (Maxim Roy) was kidnapped by the evil Shadowhunter Valentine (Alan Van Sprang), Clary was forced to team with the mysterious Shadowhunter Jace (Dominic Sherwood) for her own protection, much to her BFF Simon's (Alberto Rosende) chagrin. The premiere also teases many stories that will have big payoffs later, like Magnus Bane's (Harry Shum Jr.) connection to Clary, Luke's (Isaiah Mustafa) questionable past and loyalties and Valentine's curious interest in Clary.  

But unlike the 2013 movie The Mortal Instruments, the new series is going to take its time telling the popular YA story, and there aren't any big twists thrown at viewers by the time the premiere credits roll. That's why executive producer Ed Decter thinks the show will be much more successful than the scrapped movie franchise.

The Hollywood Reporter spoke with Decter about the lessons learned from the film's failure, any changes being made to the story going forward and more.

The Shadowhunters series premiere was authentic to the book. Why not change it up? 

Decter: One of the great parts about the books is that they really should have been a television show from the beginning. One of the things the movie suffered from was just simply trying to pack enough and all of it in in an hour and a half. Basically, our whole first season is what they did in an hour and a half of a movie. We have the luxury of doling out the cool information and get to know the characters so much better and get to know the stakes so much better and more slowly than the movie. That was our goal. There's already been this very straight telling with the movie, so let's give the audience some dark, sexy surprises about how we get to certain landmarks in the book. Let's have it be understandable to the new viewers but also provide some surprises and deliver some real good, substantial things that the viewers who are readers want to see but maybe let's get there in a different way so that there are still surprises for them.

Are you going to continue to stay true to the book all season long, or will you make any changes to the story?

We're not changing the giant, essential truths that we all love about the series, but we're getting to some of those things in different way. For instance, Luke isn't a cop in the books. He owned a rare book store, which we didn't feel was active enough and involved enough for a television series. It worked fine in the novels, of course. 

Are there characters you couldn't fit into the show that were in the books, or did you add any new characters?

It's not really completely new but we have some characters that are amalgams of several characters in the books. In the novel, you can have 27 characters rattling around in a chapter if you want but just to not confuse the viewer and have an enormous cast every week, we combined certain things. Simon didn't have a girlfriend at the beginning of the book but we combined a fan of his that we meet later in the books with a band member of his and created the character Maureen. We did that to condense the story, and we eventually get to all the things that happen to Simon and all the exciting things and huge transformations that he goes through, and we get to them in a slightly different way. Honestly, the books are everywhere in the writers' room. We've also read the auxiliary series, The Dark Artifices, The Magnus Bane Chronicles, all to find little details or props we might need from those.

Which actor is putting the freshest spin on their character?

Alberto Rosende, who plays Simon, he's in fact Latino but he's playing Jewish in the show. When we first cast Alberto, people were wondering, "Will Simon still be a Jewish vampire?" And the answer is yes. Isabelle Lightwood wasn't written as Latina in the books, but we cast Emeraude Toubia to play her, and she's sensational. If the audience hangs with Isabelle, she makes such a beautiful transformation over the first season. 

What lessons did you learn from the film franchise's failure that you're going to apply to the TV show?

I didn't work on the movie, but what we learned was that just trying to compress this very big saga into an hour and a half was not the right approach. Having nothing to do with the execution of the movie, having just to do with the big concept of it, since it's a really big world and that's what it makes it great for television. We can go on and on and on infinitely renewing itself, whereas for a film, compressing it down took away from the wonder of each part of it. And in no way are we comparing ourselves to Chris Nolan, but trying to aspire to do what he did to the Batman franchise — which was taking a franchise that wasn't that old and making it dark, sexy, unexpected — that was our goal with this show.

Is the first season going to follow the structure of the first book?

We're not locked to season one is book one and season two is book two. For instance, book two takes place over the span of a week. Probably, season two is going to be more books two and three. There's really no advantage to being locked to exactly the book structure because obviously the mediums are so different. We're borrowing from all the books and using solutions in book six for some things here, but we're doling out the general giant story in the same manner that she did, in the same order and sequence she did.

What are you most excited for viewers to see from the rest of the season?

The reviews are going to say we have a beautiful cast and they were cast for their beauty. And yes, they are beautiful, but they're really good actors. If the viewers hang with the series, they're going to see real, amazing depth. You can write characters as deep as you want, but you can't exceed the talent of your stars, and they've been able to handle everything we throw at them. What I'm really excited about bringing this cast made up of mostly relatively unknowns — of course Harry Shum Jr. is well known from Glee and Isaiah Mustafa is in commercials every minute — but to have this cast of virtual unknowns to the world, I predict huge things for all of them.

Shadowhunters airs Tuesdays at 9 p.m. ET/PT on Freeform.