Libero in Volleyball?

the libero has one single job and that is to dig. sometimes they hit from the back row but that is rare. this position is best suited for the best passer on the team. they have an unlimited amount of substitutes. they can go in for any player in the back row but cannot go into the front row at all. they also cannot jump behind the ten foot line just like any other player. they also rotate like everyone else but are pulled when they get to the front. they typically are subed in for the weakest backrow diggers.