4. Constantine
John Constantine the Hellblazer is the de facto leader of Justice League Dark. A powerful sorcerer, he sold his soul for magical powers in his youth and paid a heavy price for them. Known for his trenchcoat, chain smoking, and dry British humour, Constantine is also popular enough to star in his own New 52 series as well as in Justice League Dark. So why is he a candidate for being killed off? Well, precisely because hes magical. Killing off Constantine wouldnt necessarily mean the end of the characters story as the writers could have a Constantine In Hell story arc in his own series like Mike Mignola did with Hellboy when that character was killed off. Constantine could navigate his way through Hell, as he has done many times in pre-New 52 storylines but not in the New 52, before returning to the earthly realm in a blaze of glory, maybe with the help of Justice League Dark in a prison break-ish style storyline where the members of Justice League Dark bust Constantine out of Hell. Despite his absence from Justice League Dark, the series could easily carry on without him with Zatanna as leader. The group possesses so many interesting characters with varied powers that any number of storylines exploring those could sustain the series until Constantines inevitable return. Plus Constantine is kind of a big name to matter but if he dies I expect another, more famous character to die as well. It was in the pages of Constantine #4 that we found out about Trinity War through Zatanna who saw strange visions, one of them of Constantine shaking hands with Lex Luthor despite having never met him (yet). But Lex is a treacherous bald bastard so it wouldn't surprise me to make a deal with Constantine only for it to backfire on poor John. So he wouldn't be the one to die and trigger the Trinity War because he'd have to live long enough to deal with Lex but I can see him falling in the final third.