B.I.O

A boy named Y/n was a knight of Rias Gremory he loved her and every girls the in her peerage the moment he became her servant but when he was about to confess his love for them they rejected and they chose Issei instead.Not being able to bear the pain he hides in his smile He rips out his Knight piece and ran off and then all of a sudden he disappeared,vanished into thin air but he soon returned far Stronger,Faster,Smarter and Better