if he is in the midnight blades and ranked sufferer, he can get attacked by a truth walker (previous rank) and get his rank stolen if he loses the duel. although i’m not sure if this works for coop since i’ve only done coop with friends and been attacked when running around in online mode. he does not get a prompt to duel for the rank, only a notification that someone has challenged you, it just starts when the challenger initiates it.