[quote=Erranruin]
Hey that was my idea! :OSee?
[/quote]

No that sounds like some form of American Exceptionalism turned into metal. Not Bullshit enough to work as Bullshittium. It would have to be formed by the magic of Friendship mixed in sheer Willpower. Friendship can be replaced by Hope and Sorrow. Nebulous concepts need to be backed up by belief to create Bullshittium. It then must be forged by a fairy.

Also I went too far with that.XD

Edit: To be slightly more serious Yuki could have gotten the weapon from a Demon blacksmith. She may not have known who he or she was, but maybe Yuki did something impressive and was worthy to be given a blade that isn't created with standard Japanese steel.