Playing around with designs for a sword I'd like to use in a D&D campaign someday. Upon attunement the sword begins to speak to its wielder, as a dragon of unknown nature was tricked and trapped inside the weapon by a duplicitous set of sorcerers...
Depending on how the wielder interacts with the dragon, its nature may change. An unscrupulous or cruel wielder will bring out the worse side of the creature and its abilities.