Place all of your set , unique, and legendary items in the shared chest and close the game. Then load a Multiplayer game. You may even want to play a quest or two in Multiplayer and then quit the game. Try loading a Single player game, having kept all of your unique, and legendary items in the shared chest. I hope that works for you. If not, then when you progress to the next level (Silver to Gold) the NPC follower/stalker should be gone. Remember to store special and valuable items only in your shared chest from now on.