'The Mortal Instruments': Behind The Seams

'It's very sexy. It's very edgy,' star Lily Collins tells MTV News of fantasy film's wardrobe.

If there's one thing Shadowhunters pride themselves on (besides their bad-ass demon-destroying skills) it's their ability to look better in black than the widows of their enemies. And it's not just all talk, as we learned while visiting the Toronto-based set of "The Mortal Instruments: City of Bones."

As director Harald Zwart told MTV News, the main challenge for costume designer Gersha Phillips was to create a look that was fresh yet familiar.

"How do you find a kind of goth, leathery look that hasn't been done a million times before and not too S&M and not too this or that?" Zwart mused. "It's search and find."

"It's very sexy. It's very edgy. It's not costume-y. It's very much a look," star Lily Collins — who plays Clary Fray — explained of the Shadowhunters' gear, which she sports later on in the film after learning she's not as mundane as she once thought.

"It's not easy to do stunts in boots and heels and leather and wearing a harness under tight leather pants," she continued. "That's a little difficult. But it's been really fun."

Another Shadowhunter staple is something just as dark much less ephemeral: powerful tattoos known as runes. The black markings, which cover the warriors head to toe, imbue them with heightened abilities and senses and are a necessity for fighting off foes. Unfortunately, in real life, they don't come with the ability to fast-forward time, meaning applying the intricate ink could take upwards of three hours.

"They're kind of a pain in the ass to put on in the morning," bemoaned Kevin Zegers, who plays Alec Lightwood.

"It takes about three hours," confirmed Jamie Campbell Bower, who plays Jace Wayland. "We've managed to cut it down to about two and a half hours now. I will sleep in them sometimes. I won't shower. I'll stay in them, and then you come to work the next day, and it cuts down about two hours in the chair."

Of course, not every character wears Shadowhunter black, but that doesn't mean they aren't just as stylish. Take warlock Magnus Bane — played by Godfrey Gao — for instance, who was pants-less the day we visited set but had plenty of other embellishments to flaunt.

"I've put on glitter, eye shadows, nail polish, really glittery lipsticks, and I think I do have the red-powdered cheeks going on," Gao said with a grin.

"The Mortal Instruments: City of Bones" hits theaters August 21, 2013.

Check out everything we've got on "The Mortal Instruments: City of Bones."