Board Thread:Destinypedia Forum/@comment-70.68.115.104-20141006065907/@comment-108.232.76.56-20150626204425

64.4.83.226 wrote: It's not unreasonable to suggest that they will add another subclass for each class; you can clearly see a third space in the menu. If they do, it seems silly not to base it on anything but the missing element (Void for Hunters, Solar for Titans, Arc for Warlocks). If you think about it, there are also three diffrent "types" of supers. Summons (golden gun/ward of dawn), Modes (radience/arc blade), and Attacks (fist of havok/nova bomb).

So I'd say that the super for an arc warlock should be like, summoning a thunderstorm that lashes out at enemies who get near the area it was set. Like, a more powerful version of the titan's arc grenade.