Board Thread:Speculation House/@comment-85.130.101.225-20130816112245/@comment-1028961-20131113102003

It's entirely possible that the "mystical aspects" of the sword and shield are just manifestations of Jaune's Aura. There's never been an in-depth explanation of what exactly Aura can do, so we can't say for certain whether they amplify or direct it. It's a possibility, yes, but there's nothing to really prove it at this point.

Also, since it's been passed down in his family for at least 4 generations, they could be from a time when weapons just didn't have any of the same special abilities that "modern" weapons like the ones used by the other characters, and the only thing that makes them special is that they're really freaking durable to still be in such good condition after so many years.