Gjallarhorn is one of the most storied guns in the Destiny franchise, and its return to Destiny 2 has come with some fanfare--you'll have to complete the new dungeon, Grasp of Avarice, as part of the game's new Bungie 30th Anniversary celebration DLC. It's worth doing, though, because Gjallarhorn is just as powerful as Destiny 1 Guardians will remember. And once you have the Exotic rocket launcher (use our Gjallarhorn guide if you want to know how to snag it), you'll want to unlock its...