X'ian X'xar got these boots off of a Gnoll, but it is certain that this gnoll did not make these. It is also obvious why this gnoll no longer holds these boots.

Abilities
These boots have the ability to phase the wearer within 10' of his or her original position. Only wearable by thieves and assassins.
 
These boots are cursed, and causes massive foot pain and discomfort.