A while back, I did a dreamcast for the movie, and in the comments of that post, a fellow blogger and I had a rather interesting discussion about one of the most important characters, Prince Rilian. Though the book would be impossible without him, this key character actually gets very little time devoted to him. We know little of his personality or history, only the scant details given to us for the purpose of the story.
#6: He is DESPERATE
This is the trait that we see the most in the book. After being taken captive and enchanted by a sadistic witch, forced to become her mindless and devoted slave for ten years, Rilian is understandably miserable. He is desperate to get back to his kingdom and his father, and sickened and horrified by the nightmare he's had to endure for so long. He is powerless against the witch, and though he has tried to escape many times, she has always managed to bring him back under her control. She is terrible! She is incredibly sadistic. Her goal is to take over Narnia using their own beloved prince as her weapon. She would crush their spirits by flaunting her control over him, and torture him with the humiliation and pain of having betrayed his own people. She gives him one hour of sanity every night, seemingly just to rub it in, knowing that he will never escape.
In the book, during Rilian's plea to Eustace, Jill, and Puddleglum, he refers to himself as "a wretch who has suffered almost more than any mortal heart can bear". If that's not desperation, I don't know what is. He states that one night, he even broke though the ropes that keep him tied to the silver chair during his hour of sanity. That's a pretty incredible feat of strength- and it was induced entirely by the adrenaline of desperation.
Even when he is under the spell, it shows through. Though during the day he thinks that he is in love with the witch, and that his only care is to sing her praises, some corner of his mind knows that he is afraid and miserable. He specifically asks the Travelers to sit with him during his hour, stating that he "dreads being alone". Subconsciously, he knows that he wants them with him because they are his only hope.
This trait is perhaps the most defining of them all, and is one of the only ones that is able to cut through the terrible spell that binds him.