Gremory's new power. (neglected Rias x male oc x dxd harem)

What if Rias had a sacred gear that her family never knew about? at a young age, Rias has always been ignored by her family because she doesn't have destruction magic. Because of this, she was cast aside and was completely ignored entirely. Not being able to take the neglect anymore, she ran away from home with nowhere else to go. Eventually she met a boy named Toad Hyodou, a boy who isn't perverted like his twin brother Issei. Both Toad and Rias grew close and soon fell in love. She told him and his family about the supernatural and they were surprised to say the least but they still accepted her as a part of the family. Years later, Toad and Rias are engaged but Rias mentioned that she's ok with her fiancé having a harem. And since Toad is a high ranking devil, he gets his own peerage in which he is the king and Rias is his queen.