User blog comment:B214/DxD Zero: Sirzechs story/@comment-2003:45:5D00:9D00:D59D:7785:ABEF:4D2C-20181006195431/@comment-2601:8C:601:5692:A51E:D945:8E69:D900-20181008211707

Correction, it was Bidleid's unnamed younger brother (still not Shalba, unless later revealed otherwise). Just read the spoilers.