The weapon has elvish writting on the hilt, which describes the power of the blade and a warning to whomever may use it. the main users are elvish warriers and members of a royal family as it is normally handed down a family line. The blade is made of platinum which shines mother of pearl and when commanded to it can submerge itself in boiling water which can get up to 110 degrees. The attacker can not withstand the blade near them or on there skin, as the blade enters the body the boiling water will burn them from the inside out within a matter of seconds.
Magic should have side effects, both expected and unexpected - fortuitous and deplorable. Expected side effects add anticipation, while unexpected ones increase the drama of the scene. The result can be comedic or dire, it dpends on which circumstances work best for your game.