After Losing My Memory, I Kissed the Devil on Behalf of My Dead Sister

In order to find out the cause of my sister's death, I pretended to be her and returned to my powerful brother-in-law. He lost his memory and imprisoned me tyrannically, but he fragilely whispered my sister's name late at night. I carefully acted gentle, but I was almost exposed because of my mango allergy. When his memory came back to life, he pushed me against the wall with scarlet eyes: "Who are you?" I smiled: "You are the one who sent you to hell." - But why did he kiss me more fiercely?