User blog comment:B214/Volume 22 spoilers/@comment-95.90.227.198-20170201191840/@comment-28087053-20170202183827

Thank you Benia Lover ! Finally someone that understands. Issei's power comes from ophis power plus Red's. It's utterly bullshit that Vali surpassed him when he only received a blessing. He did not use the same amount of power issei used. That's why issei body couldn't resist the power he unleashed from ophis.