User blog comment:Stbk22/Possible Power up's/Techniques for then new group DxD/@comment-3965848-20140208111421/@comment-24501441-20140208124937

It's also been stated that because of absorbing Issei's blood, Vritras consciousness began to awaken which eventually allowed Vritra promotion when he got the other three sacred gears, so it's effect has already been felt. Unless your talking about him absorbing Issei's blood in the future, in which case Issei will have Ascalon to cut the line next time so Saji won't be able to fight him the same way.