Ssosia

About

Ssosia is the daughter of the Demon King Pedonar and the second demon of the universe. She's also the creator of the Fantasia System, which created by allying with her aunt Parmael, which later betrayed her and imprisoned in her homeworld. After an strange events series she end up marrying Kang Han Soo and became one of her main allies through the series.

(Source: FFF-Class Trashero Wiki)