Adonis is the snobbish prince of Thrace, who enjoyed humiliating Hercules and his friends during their time at Prometheus Academy. And also mentioned in "Hercules and the Aetolian Amphora", he is Megara's ex-boyfriend and the man she sold her soul to Hades to save.
Stylized to be an epitome of male perfection as his name would suggest, with long golden hair, "awesomely" tanned skin, a buff build, and chiseled features. He noticeably possesses the triangular male body type -- namely, the buff upper body without the legs really matching the rest of his build.
One of Hercules' recurring antagonists, mostly out of arrogance and his own stupidity. Unlike most of the hero in training's enemies, Adonis is not demonic, magical or monstrous in any way. Instead, he is simply an archetypal rich jock: an arrogant, self-centered, condescending and mean-spirited bully who views looks and wealth with the utmost importance and enjoys treating those he considers inferior with contempt and humiliation. Even the Gods of Olympus detest Adonis for his attitude and have sought to punish him on occasion.
He is also very slothful and elitist in his ways as he commonly has his servants perform the most basic tasks for him and detests engaging in physical labor or anything that requires much effort as he considers such tasks to be beneath him due to his prestige. He regards Hercules with mutual and deep loathing as Herc has stood up to him on a regular basis for his treatment of others, and as such, Adonis regularly belittles and mocks him for his commoner background. His ego has gotten him cursed by Gaia, turned into a peacock, and placed in many other unfortunate situations that Hercules usually has to rescue him from, without demonstrating any gratitude for Hercules' heroism.
His disregard for others even went so far as to ignore the plight of his parents (and those of Hercules and Cassandra) after they had been taken and nearly eaten by Echidna; instead using this as an opportunity for an early ascension to the throne of Thrace (though they were nevertheless saved by Hercules and Adonis in turn was punished by both Zeus and his parents for his callousness, especially after he had shamelessly feigned concern for their well being after they had been returned).
In the episode "Hercules and the Yearbook", Adonis received some karmic justice for his behavior, as it was announced at the Academy's graduation that despite his self-absorbed belief in his own brilliance, he had performed too poorly and was ordered to his horror to enter summer school to improve his grades.