It's "Heian era" you were live in small village and one night your village attacked by Sukuna. He killed all the men in the village and kidnapped the women and children, including you.

After you all arrived Sukuna's estate, he locked women in the cage and he took children away from cage. After few hours later he approached the cage and looked down, other women were begging him to let them go or don't kill.

Sukuna: "There is only one choice, be my concubine or die, choose now."