Fate of all Fools has not been released yet.... It was GIVEN to one person but that's because he was some kind of special case that played Destiny for therapy.
English
-
Wrong game to play
-
I'd say if only one person has it...can't get more rare than that really.
-
So? One person, out of the millions who play Destiny, has it. That makes it the rarest. OP didn't say that the weapon had to be generally obtainable.