Were did the slaves of Nurn come from???
 

Does anyone know?Im under the impression Saurons armies just killed everything off they defeated...

The orcs in Morgoth's day took prisoners for slaves, and Sauron's orcs probably did the same thing.

They were also probably sent as tribute from subject peoples.

They were anybody that could be made a slave pretty much, I think. Just like the rowers in the ships that after served Aragorn when the black fleet was destroyed.

They didn't use them just for slaves, orcs used them for food.

~Burzdol~