Arrow's mystery, a counterpoint to the 'Who's Zoom?' question over on The Flash, is even bigger and potentially game-changing. At some point this year, somehow, someone is going to die. And it's going to be big. So big, in fact, that this version of Oliver, the changed man who has long-since vowed never to kill again, will state that he's going to murder the person responsible, presumably Damien Darhk (unless there's a big twist in the offing). Six months later was the timeframe for the funeral, so it'll be a while yet before we actually find out who it is (Quentin, Laurel, Thea, or someone else?). Some subtle teases and moments of foreshadowing, even if it's for multiple characters to really keep us guessing, would make for some very interesting talking points during the mid-season.