Why does he wish to be a devil? Most of the reasons like longevity, power doesn't matter now that he's combined with Vitra. Also none of the reasons he's declined being one has been fixed. Does Rias even have the power to reincarnated him? He has Cu's spear, a SG that's probably Longinus class, base power higher then Issei, and magical knowledge. 8 pawns we're good for Issei since he was absolute trash.