Slaves of Harad are farming NPCs found in various structures in Near Harad (Biome). They spend their days tending farms or standing sadly in cages. They are easily recognizable by the hoe they hold in one hand. Although they are technically part of the Near Harad faction, good NPC's won't attack them. Slaves are either of Gondorian, Haradric, or Morwaith descent.
After having bought one, your submissive "possession" follows you around (also through fast-travelling), calling you "Master" until you decide to interact with it by right-clicking. You can talk to it and you can also dismiss it. The best use for it is to seek a suitable place to start a new farm. Rabbits will also not try to eat crops guarded by slaves.
They work similarly to other farmhands. They will help you sow and harvest crops if you give them the seeds. For more information, please check the farmhands page.
Slaves of Harad are sad and pathetic creatures. In as much, Slaves that are not imprisoned in cages will plant crops, chase of rabbits, and grovel. Like civilians NPCs, they will attack only if you provoke them (by attacking them or killing an ally NPC in their vicinity).
About attacking or not, these guys are special. Indeed, according to their names, they will behave like civilians NPCs of four potential different factions, respectively Gondor, Near Harad, Morwaith, or Taurethrim. For example, if you kill a corsair near to their cell and then you free them, the slaves with a morwaith or harad name will attack you while the slaves with Gondor or Taurethrim name let you in peace. However, all slaves are considered by alignment mechanic as belonging to Near Harad faction : killing corsairs next to Gondor or Taurethrim named slaves won't necessarily give you alignment with Taurethrim and Gondor.