A long time ago, the battle between angels and devils was still raging. Archangel Arius fell in love with devil Lilith and defected. This unholy union of angel and devil brought an offspring of humans. Afterwards, ...angels won the battle with devils and sealed three Devil Kings temporarily with the Sealing Stone. However, angels have differences of opinion on how to deal with human beings. In the Angel Congress, Sherri admitted to protecting human beings and also granted human beings the duty to guard Sealing Stone. The human hero King Lee Twist who had once sealed Devil King was in turn lured by Devil King and proceeded to lose his mind. The Sealing Stone loosened and Angel Congress was disappointed with human beings. Therefore, in order to save human beings, Sherri gave up her angel status and came to the earth to find the Sealing Stone with human beings. At this time, the daughter of Devil King, Sia, found the Sealing Stone and became the new Dark Goddess. Even though Sia was Sherri’s friend, she had to kill Sia. As the one who sealed the Devil King, the fate befell to him and memories of the battle are destined to plague his mind forever.