(The past) A young woman opens a box she finds under rubble at the ancient ruined castle site. It possesses her with a god’s power, but in exchanged it killed/sacrificed her younger brother and also set loose an evil in to the world along with a curse. A curse prophecy about the fall of the 5 great kingdoms.
(the present) That woman is now queen, an old mad queen! Her husband has died some time ago. She has six children. Five sons and one daughter. And now she is babbling random things about the curse. That on her death, the evil possessing her is going to take over a new host (the daughter), and her sons will go mad and lead it’s army to destroy the five kingdoms.
Thus sons and daughter go on a quest to uncover the mysteries and history of the ancient castle ruins, the origins of the curse, and how they might break it before their family falls.