User blog comment:B214/Volume 17 spoilers./@comment-81.147.155.166-20140219215239/@comment-3965848-20140220070006

It looks too dark to be Euclid's Scale Mail so it's likely it is Saji's whos Sacred Gear(s) and sealed dragon are colored black and I bet thrice (three times) as much it is.

Plus it's stated that Euclids Scale Mail looks similer to Issei's with some slight variations, that one was way off.