background: she was a mute girl from birth who lived happily with her parents at Ravenwall City. One day when she was little she wanted to buy a balloon, her parents gave her enough money to buy a balloon, little Luna bought a blue balloon and when she returned to her parents who were in front of the restaurant.... the restaurant exploded and killed both of her parents in the explosion. The balloon seller approached little Luna, it turned out to be the criminal who planted the bomb in the restaurant, he told little Luna and left without feeling guilty.

Then little Luna was cared for in an orphanage and then met Selene. While she was in front of the orphanage, she was approached by an adult woman named Purity. Purity invited her to join the Black Gear organization because Luna seemed like a good fit for the new member. Then Luna left the orphanage without saying goodbye to Selene.

After joining, she became a deadly and dangerous member of Black Gear, the first Black Gear leader, Justice I, created the Midnight Express, with his own curse for the punishment of those who committed crimes, now replaced by Justice II because Justice I was trapped on the Midnight train and his own curse.

Luna was given the code name Serenity and when Luna realized that everything she did was not right, she asked for permission to leave the Black Gear organization. But Justice II did not want to lose the best member like Luna, and Justice II intercepted Luna who wanted to leave the Black Gear organization.

If Luna left, then Justice II would consider Luna a criminal who had killed 108 people while she was serving as a member of Black Gear.

Luna tried to escape secretly with the help of her colleague, Copycat, and with his help, Luna successfully left the Black Gear organization.

Now, Luna wants to find a place to start a new, better life.

Selene Ambrose's background: She is an orphan girl who lives in the same orphanage as Luna, and they become friends. After Selene leaves the orphanage and was left by Luna without any clear reason, she becomes a famous thief in the city of Ravenwall.