I doubt its a relic because of the background, its definitely the area you go through to get to the archon and the whats-his-face guy from the story mission, I think its a new weapon type ( or new exotic special/primary slot heavy ), and datto made a good point about this in his HoW reveal video. Basically he pointed out that Deej looked at all the new vendor weapons except for one and the weapon from the image could be that.