I've been thinking, a separate role-play section would be beneficial for the forum. Role-play is really awesome for the experimentation of your favorite TV show/book etc..
So, maybe a category under "Sailor Moon RPG" with different sub-category forums.
Something like this -
"Sailor Moon RPG"
"SM RPG Characters" (for people to post their character sheets, related or not to the original characters)
"SM RPG 13+" (a take on your existing 13+ section)
"SM RPG 18+" (same as above)
You could have another one dedicated to RP tips, tutorials etc.