Hàoyú Luong, also called Hao for short, prince of the neighboring Lóng Imperium, a royal nation located east of the Solaria Empire, second child of the Sovereign Zixuan, and younger brother of Crown Princess Sena. He travels to Solaria in order to improve relations between his homeland and the empire due to past tensions, offering both gold and also himself as a marriage candidate to Crown Princess Aurora. Though he seems to be hiding a secret, being unusually knowledgeable about things.

Sena Luong, the crown princess of the Lóng Imperium, located to the east of Solaria, daughter and eldest child of Sovereign Zixuan plus older sister of Prince Hàoyú.

Zixuan Luong, is the current sovereign and ruler of the Lóng Imperium residing in the eastern region from the Solaria Empire, and the father of Sena and Hàoyú. He was previously at war with Solaria's last emperor, Raphael, which was continued when the man's older son, Augustine, ascended to the throne, though was ended when his younger one, Alexander, became ruler after usurping his half-brother. Since then, the two royal nations have maintained an uneasy alliance.

Tienyuu, Hàoyú's right hand man and bodyguard who travels with him to the Solaria Empire, with the two having grown up together since childhood.

Haeun-Jun Lee, Princess Sena's royal handmaiden and close friend since childhood.

Shingen Masumoto, the captain of the Lóng Imperium royal guard/army and loyal servant to the Sovereign Zixuan. Also the sword teacher of both Princess Sena and Prince Hàoyú.