User blog comment:Ixarising/High School DxD Dream Battle/@comment-112.211.199.137-20140208063905/@comment-1359322-20140208125247

So? Having power to rival God doesn't necessarily means that they could defeat them. Plus Sirzechs in his true form is stronger than most Gods to the point he could be placed in the Top 10 strongest being. Issei and Vali, even if they master their current powers to the fullest, like i said could only be around Ultimate-class Devil/Angel at best. For them to reach God-class, they would require more training, but that probably takes a few years too.