Daida seems to harbor a deep-jealousy of Bojji, both for Bojji’s position as the heir of the Bosse Kingdom, and because of the attention Bojji received when they were both younger.
However, it’s difficult to gauge how many of Daida’s thoughts & feelings are truly his own, and how many are a result of the influence of the Magic Mirror, which has been advising him in private for years. The mirror seems to be the source of most of Daida’s overly-arrogant and destructive behaviors, while his more noble traits seem to be inherited from the people around him.
Bebin in particular seems to have been a good influence on Prince Daida, teaching him to value his own strength and value his personal potential. This has enabled Daida to resist some of the worst influences of the magic mirror, though Daida still refuses to discard it.
In spite of the Magic Mirror’s manipulation, Daida ultimately refused to drink the “strength potion” it concocted for him, saying he’d rather rely on his own strength than the sorcery of the Mirror. Unfortunately he was not given a choice in the matter, and was subsequently forced to consume the Mirror’s potion.
Currently Daida’s body is possessed by a reincarnated King Bosse, while Daida’s soul is forced to wander a strange abyss apparently inside of his own body.