Xin traveled to the world of DxD and became Grayfia’s younger brother, the only heir to the Lucifuge family.
And obtained the God Blessing System, from then on Xin walked the road of crossing the world to conquer his family and become the strongest demon king.
Saeko Busujima: I swear by the honor of the Busujima family, I am willing to be Xin’s Knight.
Shinobu Kocho: As long as I can save my sister, I am willing to be Xin’s Bishop.
Esdeat: If you want me to be your queen, then defeat me!