Hyoudou's secret

Issei dissapeared after a fight with a stray demon. After a month full of hopes Issei returns home togheter with his big brother Ryo. But what if Rias actually knows Ryo from her first year of high school? Can Issei stop Ryo from stealing his harem by accident or would Rias change her favourite chess piece? [OC x Rias][a litle OC x Akeno]