The crimson haired red dragon empress (HSDXD harem x OP male Gremory oc)

What if Rias wasn't the heir of the Gremory family and wasn't even a Gremory at all? What if a crimson haired boy was the heir of the Gremory family? Rias Hyodou is just your typical high school girl living a normal high school life. The only problem is that she's a massive pervert that dreams of being the harem queen. Despite being a pervert, she's also a weeb. She was asked out by a guy one day and she agreed. However on the night of their date she was dying by the hands of the guy but her life was spared by a boy with the same hair color as her and thus she became a part of Toad Gremory's peerage as his pawn. Overtime, she fell in love with him so she gave up her dream of being the harem queen. But as for the Gremory boy himself, he will be the one who will have a harem.