Rias old mistake(High school dxd x male autistic reader)

Rias made a mistake years ago. Before she started to hate Riser the two were dating and they did it unprotected and a child was born out of this. Rias coudn't assume her role as a mother so she opened a portal trought dimensions and she throwed the baby in it. What she didn't knew is that baby was sent in a dimension where time go faster than her dimension an it was a dimension full of powerful people. You were raised with those people and they thaught you their abilities and their philosophy about life and battle. One day they told you where you came from and you decided to return to the world you were born and you meet your mother and her peerage. And let's just say it don't go that well