Unless your talking about characters people have created. This RP Is a Multi-Fandom Asylum RPG which does not have any characters created by players. Atleast i dont think there is
The Characters in the RP are all from various Books, TV shows, movies and games. Characters like Frodo from Lord of the Rings, Scar from Fullmetel Alchemist, Davy Jones from Pirates of the Caribbean and Caim from Drakengard. All the characters from that RP are from various stuff like the things mentioned above. Heck there are even characters from anime shows i've never even watched
Alas, i am not the creator of the setting. It would probably be easier asking him/her if it's okay doing a fanfic based on the setting of the RP. like i said, most of the playable characters are from various media like movies, games and books. Still, if it's a bad idea i will stay away from making a fanfic based on the RP