[…]
In that army are Magnus (Harry Shum Jr.) and Luc (Isaiah Mustafa). What can you tease about how they play into the finale?
McNamara: Well, we’ve seen the unrest in the Downworld from the beginning of Season 2, and things are finally coming to fruition, but it’s forcing leaders like Luc and Magnus and Alec (Matthew Daddario) to make these difficult choices, where they truly have to choose between their heart and their duty to their people.That’s when it becomes difficult because you have Luc and Magnus, who are downworlders and who have to think about their people, but also Luc is basically Clary’s dad and Simon’s dad and the person who looks out for all of these young folks. And then you have Magnus who is so in love with Alec and wants to be there to support him but can’t because he also has to support his people. It’s these sort of difficult choices that will shape the future of the Downworld.
[…]
Source: tvguide.com