Names of a series of books. Fantasy

I believe in one of the books an elf makes his way through a maze to find a black crystal of some sort. And when he leaves the maze there is an army outside waiting for him and he uses it to kill the army.

Also I believe in another book they are trying to make a sword, they find a blacksmith with an amazing one already made. He won't sell it, but he says if they get the material he'll make them a new one.