Dupre was the commander of the Holy Knights. He is a powerful, tall and muscular warrior well known as the knight in silver armor, though kind hearted and has high regard for life.
In the past, he was the father of Sun, and was married to an unknown diseased wife. It was revealed that he has been injured in many exhibitions. Evidence showed that he had a crescent moon shaped scar on his leg, and half of his right ear chopped.
Dupre tried to seal the Seed of Chaos inside Regret, but failed and was killed by Osiris.
During the storyline, Regret mentions Dupre, calling him "father" when doing quests. It wasn't until Charity learned that Dupre WAS the commander of the Holy Knights and father of Sun. When Regret became commander, Sun found Dupre's journal and learned that Dupre's reasons with why he left, making her relationship with Regret bitter.
Upon Regret defeats Osiris, Dupre will tell him that they don't know if their decisions are right or wrong, but they won't know until they try.
In Zenonia 4, Dupre does not actually appear, but is Azimet in disguise.