kubikiribocho (Zabuzas sword) users

So I've just watched Itachis back story where he joins akatsuki and Jūzō has the blade but this was after Might Duy did his thing so does that mean Zabuza went out to find the sword also who made him a member of the 7 swordsman of the mist idk im just not sure on how this all works can someone please explain