it's been mentioned in ep 15 that the current emperor was Rykell's friend in war, so at least it put them in similar age.
yah it will be a
very
long
story
but
the tl:dr version is :
Bellerophon confessed to Maybelle that he is a prince, but his existence is hidden so that the emperor doesn't know that his child survived the gruesome experiment.
(Phon became an experiment subject when he still a fetus inside his mother's womb. the mother escaped and sought help from Maybelle's mother.
Rykell then took the kid as disciple to protect him, but he refused to raise the kid himself and left him under Khan and Duchess Kyle's care. Rykell never hate Phon although the kid is technically his enemy's child, and still went through a lot of crap by taking responsibilities for any disaster caused by Little Phon's uncontrollable power.)
Guys I think that Bellerophon and the emperor are brothers. first off they have the same hair but not only that they also look alike and they HAVE THE SAME EARRINGS the emperors are blue and Bellerophon's are red AND Bellarophon also knows his way around the palace. like he is clearly his brother.