Warning Spoilers ahead The quest for the Rat King is by far my favorite quest line in Destiny2 so far. I've played it through on 2 characters now just to be sure I wasn't crazy. On the last mission, at the end, there is an objective called "Chances and Choices". You are to kill either the Fallen Knight, or the Taken Captain you've been hunting the whole time. If you Kill him, the quest ends and nothing really special happens. But; if you stand there after killing the Knight, he acknowledges your help and respects you for it. He leaves after confronting you and allows you to take the reactor he's been seeking this entire time, or perhaps his intention was to just keep it out of Fallen hands. It's amazing to me how the game, for a split second, shows us the meaning of discretion and empathy. It's not "just a game" and the passion put into the small details will keep me coming back until the end. Thank you Bungie. tl;dr: Don't kill the Captain at the end of the Rat King quest and watch what he does.