When wielded in combat, whatever this sword strikes is transformed into mist for 10-40 seconds. Shields, swords, etc. that are used to block, intercept, or deflect the sword are turned into mist independently. If the sword strikes a creature or its worn armor/clothing, then the creature and all its current equipment are turned into the mist form.
While in mist form, the creature may use mind abilities -- psionics, concentrating to maintain a spell, etc. -- only. It is unable to move or act in a physical manner.
After this interval, the mist pulls together, and the object or creature returns to its original form. If the mist is dispersed or blown away, then it will take it longer to reform. The amount of time needed to reform is at the Loreteller's discretion.