User blog comment:Raababukk/Possible New Power ups for Issei Hyoudou/@comment-23853100-20131014054544/@comment-1359322-20131015012921

Not really sure if he can use the Longinus Smasher anymore or not, since that time Issei was able to use it after he fused with Great Red. Yes, his body is currently made from Great Red's flesh but that doesn't mean he can use Great Red's power. Maybe only a tiny portion.