Poeople have been converting for a while. for example
http://botgirl.blogspot.com/2011/04/why-i-dumped-my-personal-facebook.html
here is how
http://sayingitsocial.com/how-to-convert-your-facebook-personal-profile-to-a-business-page/
To create a Fictional charcter from scratch rather than converting:
Go to Face book
If Logged In Log out
Click on create Page link right at bottom of Sign up Page.
On create a page Click on Artist, Band or Public Figure
select Fictional character option.
Follow instructions from there.