Fun Story idea ( Tian Guan Ci Fu x Danny Phantom )
The Calamity Ghost Kings of Tian Guan Ci Fu meet the Protector of the Infinite Realms and not all dead Danny Phantom. Aka Daniel Fenton.
Imagine that the Infinite Realms are like a different flavor from the Ghost Realm of the TGCF. The Ghosts of both don't like the others. As the DP ghost feels slighted the TGCF Ghosts doesn't feed off of Ectoplasm. Or they (TGCF) think eating Raw/Absorbing Ectoplasm (or it goes by a different name) is just gross.
So imagine Danny's surprised there are ghosts out there that are not Ecto-entities. His ghost scenes still triggers.
I would think that Future Phantom would be Clarified as. Calamity.
Either Danny gets a culture shock going to the Ghost Realm Night market.
Or Hua Cheng is sitting across from the kid eating a nasty Burger to figure out a new recipe to add to his collection.
Either way your choice. My rambling is primarily from my knowledge of DP.
