User blog comment:B214/Volume 23 discussion blog/@comment-30048084-20170320194520/@comment-10330822-20170320204716

Well, Outrage Tiamat probably could do some serious damage, since Outrage Fafnir wrecked Rizevim, and Tiamat's even stronger. But you're right, if chances are Issei's probably still too strong in pseudo DxD for Tiamat to seriously kill him.