Replace ally damage with 10% damage.
It's a good weapon and imo it's better than a non ancient torch or furnace on monk.
It frees up an inna slot, so that means you can replace the belt (vigilante or WH for example) or chest.
It might work well with Inna's weapon + belt, crudest boots, and 5pc Raiment? At least there seems to be a lot more options in 2.2. I don't have ancient torch or furnace, so this is actually one of my better weapons.