ferio
in the anime, ferio has no memory of his early childhood. the first things he remembers is being trained by his master. in the manga, ferio still remembered that he was the princess' brother, but he had left her side for reasons unknown. his title of prince is a burden. as we quickly learn, he can take care of himself just fine.
while at first ferio is selfish and manipulative (he has a talent for using people and situations to his advantage), as the first season progresses, we see him change. by the time the second season rolls around and he is reunited with the magic knights, he is, on the surface, a completely different person. he is much quieter, less rowdy and flirty; he's been saddened by the death of his sister and sombered by the crmbling of his country.
we see ferio as being a very comforting and supportive friend. he grows up so much as the series goes on (moreso in the first season). it's very difficult to sum ferio up, because he's such a complex and realistic character. actually, fuu just barely beats him out as my favorite. ;D