There are those guns which require you to experience Destiny 2 in its fullest. The Rat King is one such gun, a sidearm whose power grows exponentially when paired with other Guardians who also wield it. Getting your hands on the Rat King first requires a trip to Titan to complete some world quests, at which point you’ll get the quest at the end of “Enemy Of My Enemy”. It’s a quest wrapped in riddles, where the real treasure is friendship. And more guns.