User blog comment:B214/Question & Answers 5/@comment-207.96.205.2-20160517060930/@comment-207.96.205.2-20160519034946

why are saying that the issei race is that of a reicarnated devil rather a humanoid dragon.

i do not believe error  by deducting(by news in LN) the evil piece also changes the souls of reincarnated devils. and issei race and body is humanoid dragon. reference volume 12 and 21.

go anywhere and you will see that the soul is bound to race for a living organism.

the evil piece change the breed and the body of a living organism in devil while keeping as much as possible their form and power of origin.

the reason that evil piece also changes the soul is to connect them(reincarnated devil) to their master(way of talking) and get them used to their new body, but think their human remains.

remember how Rias knew Issei was still alive. volume 11

well, again, thats gods and bouddha and ophis/lilith and great red(true dragon)/ISSEI(SMALL TRUE DRAGON) can not become the reicarnated devil or angel, the brave saint using the same system of evil piece.