User blog comment:B214/Volume 22 spoilers/@comment-95.90.227.198-20170201191840/@comment-95.90.227.198-20170203210157

Yeas, she has not given her Powers to both of them, but Issei has Ophis Power in him, because he was born with them (his 2nd Birth)

Thers on verse from many that stayed that Issei was born from Great Red`s flesh and Ophis Power ( but later its also stayed that Issei has both Ophis and Great Red powers or was born with them, but I think therse more with Issei body and maybe there is a hidden Power in him) Also logical Issei who was born from Great Red and Ophis should be a Dragon God because his flesh power and Auro should be the same as Great red + Ophis if we were logical.

"Issei's life force is currently unreadable due to his body being made from Great Red's flesh and Ophis' powers. At its lowest which is zero it represents "dream" or Great Red and at its highest which is infinite it represents "infinity" or Ophis."