'Add Your Own Fluff' D&D Cursed Item: Cruel Activation Word!

  I had this idea... What if a player finds a really nice magic sword...

  To activate it, an arcane-sounding word must be spoken. What's cruel about the word? Well, it's actually a demon's name...

  

  Every time the demon's name is spoken to activate the magic sword, there's a cumulative 1% chance that the demon will hear it and appear before the one who spoke it. (So for example if the sword-wielder spoke the name eleven times since he has the sword, there's an 11% chance the demon will appear the next time he uses it!)