the artefact

there is an artefact called the blue sword. it says to make the one yelding it unstopable. but no one knows where it is. it was made by three powerful witches and given to an skilled swordsman. the swordsman killed an demon with it but then he was killed for the sword. the witches descided to hide it and gave it to an smart constructor. the constructor hide it and made an key. no one knows how the key looks like and so the sword became a legend. but there are still people looking for the sword and the key to its hideout. You are having this key in your posession or are the key. have fun