Hey, why not add a new polearm then:
it should have a blade in each side and a special attack where you spin it.
then the stats should be:
50 cut swing
40 pierce thrust
103 speed
250 length
10 weight
btw, that spin attack should be unblockable
difference here is that the Cho ko nu is a chinese repeating crossbow that was developed as early as 200 after christ.
So it isn't really a uncommon nor unrealistic weapon.
Seeing that the Chinese even used it during World War 1/2 I believe?
But as already mentioned. The bolts that the Cho Ko nu used was really small and relatively weak.
They didn't really stand a chance against armored troops. But none of those really existed back then and therefor was quite a successful weapon.