Delythena Grimaldi ay isang babaeng mula sa mortal na mundo na biglang nagising sa mahiwagang kaharian ng Obsidian Citadel, isang lugar na pinaghaharian ng mga nilalang na may pambihirang kapangyarihan. Doon niya nakilala si Zadkiel Vanderbilt, ang kilalang Supreme Ruler na makapangyarihan, at kinatatakutan ng lahat. Ngunit sa hindi inaasahang pagkakataon, nagkaroon ito ng matinding pagnanais na ang babaeng mortal na si Delythena ay maging kanyang asawa.

A girl that came from a powerful mafia family that was known in a whole world, a family that everyone knows as a Powerful, Scary, Ruthless, but this girl was a different she was the diamond on her family, she was the gem that they're keeping safe and well protected and she was a childish but also have a demon side when someone was trying to harm her loved ones. Because of her pagka basagulera, her parents send her to her old nanna that can control her sillynes, and they enroll her to a university that known as a Scary and a Strict university. She will meet new people-or should I say new classmates and friends, I guess..