Sun is the daughter of Dupre, the former commander of the Holy Knights. She is mainly a supporting character and only appears in the first Zenonia. She first meets Regret in Adonis when he was looking for the Guild of Night, and meets up with him again when she was looking for Vague for details of her father, unbeknownst that he is dead.
In the Town of Hades she learns from Regret that she is his sister, since he was adopted by Dupre. In Libra Oasis Regret receives a letter telling him to be careful.
In the evil ending, Regret eventually kills her in his anger. If he takes the good path, Sun calls him a murderer, even after becoming a leader of the group of knights in Leo.
In the good ending, (very end of game), both her and Lady Charity make an appearance, and are shown healing him or looking over him.