User blog comment:ArmInAss/Silly (?) Fan Fic Idea/@comment-24851346-20150830212152

I could suggest some archetypes.

Perhaps the daughter of a maid working there to act as the Prince's gopher? A Kikimora, Holstaur, Kobold, or other 'Domestic' breed of monster.

The daughter of a diplomat from a Monster Kingdom. Possibly a Princess, or likes to pretend she is. Could be from the Mist Continent, or Zipangu, or maybe from a rougher species, like Orc, or Ogre.

A wandering monster who fancies themselves a knight, and pledges service to the prince during the trip, and refuses to leave.

A loli witch, associated with the Sabbath. Could be an atypical witch, or maybe an Imp or Devil.