You know how there’s always been speculation that Drago’s cloak was made of night fury scales, and well, it is indeed possible
During the third film it was revealed that Drago was one of many war lords that had simply put him in charge of creating their joint dragon army. The war lords that we know of are Khan, Griselda, Ragnar, and then of course Drago, and they have more than once sought help from the notorious dragon hunter, Grimmel, who is known to have killed every last night fury.
So hear me out, Toothless is 20, which means that 20 years before that there were other night furies, which means Grimmel was still in the process of hunting them all, and 20 years ago Drago was already up to no good, so I think we can assume that there might have already been an alliance between Grimmel and the war lords way back then, which makes it very possible that Grimmel gifted Drago with the hide of one of his night fury preys.
