Board Thread:Speculation House/@comment-85.130.101.225-20130816112245/@comment-27.252.88.61-20140601095128

My personal headcanon is that it's less bubble shield and more Armor Lock; an absolute defense which basically makes Jaune an immovable object. It's possible we've seen it in Forever Fall with Cardin punching Jaune in the face and having that bright light (much more than other Aura 'pops' we've seen in the series so far) stop the blow.

As for Crocea Mors, I think that they serve best as increidbly mundane, practical weapons; they're a very, very well crafted sword and shield set that become very dangerous when applied properly and the fact that they've lasted three generations of Arcs (implied to be heroic in stature, to boot) should be testament enough to how special they are.