Excalibur is the idea been thinking of recently too. There are enough variations in the legends to give their own twist on it. For one thing originally the Sword in the Stone and Excalibur were two different swords. But in retelling both were combined into a single sword.
The only risk is that another Arthurian quest would evoke Last Crusade. But that can be avoided. By delving into the Black magic of characters like Morgan Le Fay. Giving the story darker tone.
The only risk is that another Arthurian quest would evoke Last Crusade. But that can be avoided. By delving into the Black magic of characters like Morgan Le Fay. Giving the story darker tone.