Note: When the word slave is mentioned, most people envision the American South prior to the Civil War, a rare period of particularly inhuman subjugation. Slavery has never been kind, but many periods based on a slave economy were still not quite that bad.
Among orcs, a slave is simply a capture of war, owned by a particular person, but still an individual of their own. The orc owner has a duty to feed and clothe the slave, to ensure its good behavior towards others, and to make sure that when the orcs roam, the slave manages to march as well.
Slaves are also protected by the same laws regarding brutality and murder as the orcs themselves follow, but are exempt from the shame of turning down a duel.
Brutality: Beatings are an accepted method of behavior alteration between a parent and child or owner and slave, but certain rules specify exactly what a beating should consist of. For rude behavior, a hard cuff or sprawling shove; for violating personal space, a maximum of two punches or one hit with the butt of a spear; for flagrant violation of protocols, being held down while the insulted party enacts a maximum of three punches or one hit with the butt of a spear (don't insult too many people!). For breaking of certain laws (such as slaves not conspiring to escape), the violator is tied up, and then kicked in a circle around a ring, the size of the ring determined by the severity of the crime.
Murder: Warfare and dueling are the only sanctioned forms of killing someone. All else is murder. Murder by accident or self-defense is handled with a beating ring (see brutality, above). Planned murder is handled by banishment, which is where the injured parties (friends of the murdered) stand in a line and are allowed to strike the murderer with fist or foot as he runs past them. They are not allowed to stray from their position, so once he's past, he's past.
Slavery
Athan, Greppa and Merideth were brought together along with one other human, a tough-looking, older woman who called herself Kestra. Kestra spoke the Theralis and orc tongues, and acted as a translator for the shamaness who had 'bought' them.
Over the course of a week, they quickly realized that escape was very near hopeless, and Merideth's tales of Thera's own leading of the slaves to victory was unfortunately lax on the details of how this was done.
The orcs simply lived too remotely.
They pitched tents all over the sides of the valleys, and hunted silently among the shadowed woods. And they kept a reasonably good perimeter - a slave might conceivably bluff their way near that edge, but all slaves were to stay in a careful radius of the center of the orc territory. And during tribal movements, slaves were tied together with knots devised by generations of orc cunning.
And even if they did escape, none of the three knew where to go. Never having been outside of their village areas, and certainly not outside of the Theralis valleys, they only had the vaguest idea of a proper direction.
The shamaness had moved into a mountain cave, hides stacked in one corner, an ancestral fire in the center, her charms scattered throughout. She was friendly enough. She primarily expected them to do light physical labor so she could meditate or laze about (it was hard to tell which was which), and to master the proper obeisances so that others would know she owned them.
Athan, of course, was her show off prize, particularly given his cost. She paraded him around whenever possible, and often had him carry things (such as her cauldron) that a strong orc would have winced at, just to show that he could.
Merideth and Athan, she required to learn orc, although they were mystified as to why, and they spent many hours in the company of the dour Kestra.
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A month into their slavery, Merideth had plunged into a depression, Athan was acclimating to being a Ken Doll, and Greppa was realizing what the shamaness wanted.
In halting orc, he approached her, "Olgah, I speak with you, stuff."
"Yes, little slave?"
"You teach Bone-Ache ways, to learn my ways?"
Olgah beamed at him - he wasn't female, but he had cunning in his bones, "Yes, little slave. I seek to learn the ways of your magic."
After struggling through the torturous orc sentence, Greppa nodded, then, "I not teach in orc. I teach in arcana. You learn?"
Olgah thought for a moment, and Greppa (having learned the lesson of her thinking temper, stayed quiet), then looked at him carefully. "You can not teach in orc?" At his nod, "Then I will learn in urkahneh."
Greppa, still feeling his way through orc culture, stated as carefully as he could, "Then I no use of you?"
She blinked, then parsed his meaning, "Hah! You are too small, but you would make a fine orc! Do not worry, little slave. I do not forget a fine gift!"
Greppa, not sure if he'd gotten a concession at all, also wasn't sure he wanted to break her suddenly good mood.
Over the months, Greppa began teaching Olgah the basics of arcanist magic. It was rough going, but Olgah turned out to have a grasp of magic similar to his own, and he quickly saw why she was the Bunahken shaman - there was no other role for an immensely intelligent person who was not strong enough to be a war drummer, and not vicious enough to be a leader.
While he taught her, Athan and Merideth were getting into trouble.