No, seriously.
Your esteemed ruler King Cylas Robarthe, has a rap sheet taller than his knuckle-dragging-neanderthal son-in-law. Most of that has to do with his highness's nookie seeking tendencies. There for, his highness has MANY, many, little mistakes running about and I hath declared open season on such roles!
So c'mon down to Crazy Uncle Cylas's used-up-old-whore's offspring dealership and grab your very own royal bastard! (For limited time only!)
So now, the srsness:
Character's mother would have been fairly young when she discovered the King's little 'present' growing inside her. At this discovery, she would have taken her grievance to the Royal Steward or (had she a 'relationship" at the time) the King himself. In more recent times, she'd probably take up such matters with either the Steward, or the King's Adviser. At this time, the unfortunate woman would be examined by royal physicians, questioned to death and then, should her story check out, be awarded a considerable chunk of change a marriage above her station, (though not by much) and a VERY small chunk of land to generally be out of his highness's hair and far away from his legitimate children.
The character would have been raised by a man not his or her father, though he/she may not know it. Probably in the country, as his highness typically beds young noblewomen. Still, rank matters far less than general prettiness of the young woman in question.
Much lesser women, would probably not have left the palace's employ, or at least, would have not taken her shame all that far away.
So right off the bat, there are at least three known stable hands/masters, dog and bird men, and huntsmen, who are known to have his highness's dashing good looks. It's something whispered about, but not common knowledge. The character wouldn't be proud of being a not-prince/princess and would be in no way eligible to inherit anything but Cylas's gout when they reach a ripe old age.
Still, bastards are known to have inherited a few other little things from their father: Gambling habits, drinking habits and so on. They CAN and DO end up tracking down and hitting up the old man for a little extra cash.
Have fun with it!
PM or whisper: Osanna or Cylas Robarthe
With questions, ideas and so on.
Be sure to run all ideas by me.