A so-called pleasure-seeker takes joy in other people's pain and feeds on their tears. Our protagonist, Qin Yafeng, transmigrates into the body of Irina, a nasty little brat like that: a loyal knight girl, a sadistic pervert. Could you please not have so many people with emotional debts to you?
And when he dreams, in that world that is both illusory and real, he meets Irina again, this time as a man...
This book also goes by the name "Moonmark Syndrome: Field Theory."
I was suffering through Bloodborne while coming up with the idea, so an unmistakable Bloodborne flavor was inevitable. Still, there are differences.