Hereward

Sir Hereward was a gallant knight and nobleman of the Kingdom of Daventry, under the Good King Edward the Benevolent. He was a fine and excellent knight, as was his father was before him.

Background
Hereward was a noblemen and the king's best friend. He was also the father of the king's favorite knight, Daventry's present king, King Graham. He was proud when his son was chosen to succeed King Edward the Benovolent as his heir. However, he was never able to witness the event, as he tragically died in one of the border wars which marked the turbulent last years of King Edward's reign. He wanted his son to be a scholar as well as a fighter. He left his son with valuable advice, that proved useful in son's and even grand children's adventures.

"'Boy if I have learned anything in my life, I have learned this: When in doubt, or in trouble, pick up anything that is not nailed down, and if it is, look for loose nails or boards. Check carefully into, under, above, below, and behind things. Read everything; you might learn something. Wear clean undergarments, brush after meals, and always remember: nothing is as it appears.'"

Behind the scenes
According to Rosella & Graham in Hoyle's Book of Games, Volume 1;
 * Rosella refers to her grandfather in both past and present tense, "Grandfather was a fine knight, as was his father before him." & "My grandfather is an excellent knight, of one of the finest in the realm". Graham speaks of his father only in past tense. Based on Rosella's context she is unlikely speaking of her other grandfather, Prince Cedric.
 * One of the lines may imply that her grand father (no name is given) was still alive when Graham became king. She says he was proud when his son Graham was chosen to succeed King Edward the Benovolent. Although it is possible that the decision to choose Graham as heir to the throne began long before Hereward's death, before Graham was sent on the quest to find the three treasures of Daventry.