Similar in some ways to a specialist class, a racial paragon class focuses on expanding the innate racial abilities of a specific race. Like a base class, racial paragon classes may be taken at 1st level; however, only members of a given race (or of a related subrace) may take levels in a racial paragon class.
A character can never have levels in more than one racial paragon class, even if they are permanently changed into a new race, unless a specific class feature of allows the character to take more than one paragon class.