Okay circling back here, dyou want me to stick up a prompt for Wangji to interact with wrathdragon? My best idea here is, since he's flying Hermione out to the land of Preserved Herbs, maybe they're both acting as defence and general assistance muscle there -- Wrathion staying in his true form in the blind hope people just assume he's randomly a black dragon and don't question it, lmao, since you cannot hide easily in sand dunes to change back... but then using his big size to help move and dig out any airships and swat barbed wire out of the way.

They could:

1) have sombre discussions (with staring out into the distance, and dramatic gusts of wind) around bones and stuff, around the cure and/or other dramatic staring into distance worthy things
2) fight off barbed wire
3) 1 and 2 alternated.