Overview
Slavery is a large factor for evil factions, they use it to grow and expand, using them for food and labour as well as constructing war machines, without them Sauron wouldn't be able to create his massive armies. The evil player should be able to grow their slave labour force, whilst the good player should be able to free them.
Enslavement
If a evil player has less than -500 with a enemy faction, they can enslave their civilians with a new item, a chain. When you use the chain on an civilian, a pop up will appear, you have to keep clicking to a move a meter to a green area, if you do you will have enslaved the civilian.
Once enslaved they act like current slaves of Nurn. If a slave is enslaved or hired they can't be freed, as that would be very annoying for a player that spended 100's of coins to buy an army of slaves. Enslaving people gives alignment as well as taking it away.
Freeing slaves
If you have - evil alignment (mainly the faction of the slave) you can free the slave, using a new item, a key or a lock pick. The act of freeing them is very similar to enslaving them. Once you free them, they will act like farm hands with giving you alignment.