Kim Hye Yoon as Eun Dan Oh
(18 y-o)

A cheerful high schooler. A tough girl with a boyish but cute side, can be really talkative sometime and easily punch or kick someone . She can become quite feminime and girly when she is around her boyfriend Baek Kyung, her childhood friend. Her monotone life makes her wish to change her life, and her life truly become upside down after she find a strange crystal that night.

Eun Dan Oh and her boyfriend Baek Kyung at school

Kim Seok Woo aka Rowoon as Woon
(104 y-o by Mirac Calender)

The future king of Hwon Kingdom, the most powerfull kingdom who lead and keep the peace of Miracle Planet. Hwon Kingdom hold the fire crystal and the strength of the crystal is inherited to Hwon. He has a warm and gentle character but since the doom of the planet due to the attack of Cheol army he become cold, distant and didn't talk much.

Kim So Eun as Siera
(120 y-o by Mirac Calender)

The princess of Hwon Kingdom, Woon's big sister. A chick and elegant woman and kinda fierce. She is a total opposite of her loving brother but she cherish Woon a lot. She is enganged to prince Eros but their marriage is  suspended since the massive collapse of Miracle Planet. A best friend with the royal guard Key...... And Gwi.

Lee Soo Hyuk as Gwi
(137 y-o by Mirac Calender)

The ultimate royal guard of Hwon Kingd