War and Slavery!
I did a search of the forums for topics where slavery came up, but there was no post or thread that addressed slavery in a way I wanted to - or addressed it with ideas 1 to 33 along with it, causing it to get minimal attention. So! After making clear that the idea of REAL LIFE slavery is bad, much like real life slaughtering of kittens purely so you can make totems out of their skulls* is bad, I'd like to share with you why I like the idea of slavery in DF!
First of all, I'm pro-slavery in Dwarf Fortress. When your Dwarves (or any other race as time goes on) begin having more complicated relationships with other nations, cultures and races, war becomes more and more likely.
War can be either a constant; the war against the goblin clans. There's never peace, nor any officially signed diplomatic decleration of war - it just is. The so called 'war' against less sentient monsters, who roam in packs but have no proper civilized aspects to them.
Or, war can be a bit more civilized; a war against the Elves for your genocide of entire forests, a war against an expanding human kingdom, a war against an organization - an alliance of wronged and greedy merchants, even a war against a clan of Dwarves whom have done you a great wrong.
For our example, let's say that you are engaged in the latter - a campaign against a human kingdom over a nearby source of iron. In combat, especially between proper armies, enabling your soldiers to not kill disabled soldiers in favor of capturing them is a must. Prisoners of war would have to be taken care of (or they could decide not to, and starve them out right there) - they'd have to eat and drink, be designated a place to sleep (be it the ground or a bed) and they'd have to be given protection. Protection from them hurting themselves (attempts at escaping) and protecting them from foolish outsider attempts at the same. Taking prisoners might even cause other nations to be a bit happier, seeing how you prefer saving lives instead of taking them.
Then, once prisoners would have been gathered up in a prison, either in the field or back at the Fortress, a number of options would rise to the player.
1) She could order their execution!
This may seem horrible to many 'good' players, but honestly - I make totems out of dead kittens, and many players don't think twice about 'indoor plumbing' for pesky but innocent dwarf nobles. Kinslaying! Why would they treat their prisoners any better? Especially when this can give a very clear message to -everyone-. Don't mess with THIS Fortress! We punch elephants and kill the prisoners! This would especially impact nations/races with close ties to the victims, and any/most members of the victim's races. For added demoralization, specific bodyparts can be gathered and sent back to the human kingdom. If a castle is undersiege, the dead could even form as ammo for our catapults. Executing prisoners is viewed as much, much worse than executing them in battle, as they are now unarmed, defenseless and legally considered as civilians - so to speak.
2) He could trade them back to their leaders.
Just how valuable is Swordsman Dan to his king, even after having lost an arm or an ear? How about 50 Dan's? Demanding a tribute or a diplomatic pact (even a peace treaty) in trade for the lives of the king's men can be a very, very strong move. Should the king accept, the whole thing is treated like a proper trade. Either the king sends unarmed caravans to pick up his men, or the dwarves send a caravan of their own. However, should the king refuse a deal that his people would consider fair and just, they might become terribly demoralized. Tantrums, strikes and melancholy with the prisoners families! The horror of it all! A king refusing to trade 1 sheep for every 1 prisoner might risk riots!
3) She could set them free.
Unarmed, with all their weapons and armor being taken by the Dwarves, these prisoners could be released into the wilds - to survive at the mercy of the land, so to speak. This could be done enmasse (possibly risking them to band up and return) or in small numbers. This could be done anywhere, provided a caravan could be sent there to drop them off. If they'd be set free near the borders of their homeland, this could be considered a powerful gesture of good will - the Dwarves of this fortress are not evil, unlike their human counterparts!
4) He could enslave them.
Cheap, basic workforce. Livespan is cut down dramatically, they only eat half the food dwarves do, drink no alcohol, are dependant on water to get through the day and need no luxuries. All you need is a small(ish) force of slavers, armed dwarves who look over the slaves and dish out beatings. This would be frowned upon by friendly nations, and the rest of their race would cry out with rage!
Which brings us to the slaves! The way I imagine them is ...
1) A slave eats half as much as a Dwarf. A slave will not be fed any food above 'low quality' stuffs, unless no low quality foodstuffs are available - and even then, only if the player says so. Some nobles might affect this, in case of starvation amongst the slaves. "Let them eat cake!"
2) A slave never, ever drinks alcohol unless as a reward for good service over the years OR if the player says so. However, a slave would be [WATER_DEPENDANT] or somesuch. If they're not allowed to drink, they slow down considerably. The need for wells grows with the number of slaves.
3) A slave can do no jobs beyond what might be considered 'menial', and no job can do the job at a skill level higher than .. well, 'plain', I guess. Should he be a miner, his skill could never be higher than 'Miner'. A slave can do the following things:
a: Hauling of all kinds.
b: Cleaning.
c: Cleaning.
d: Woodcutting. (Counts double when it comes to slavers needed for this group of slaves)
e: Mining. (Counts double.)
f: Smoothing. (NOT engraving!)
g: Bridge-building, road building and the such.
4) A slave must be in the presence of a slaver. Should the slave somehow slip out of a slaver's sight, it may be flagged as hostile - except most dwarves wont shy away from roughing the slave up and returning it to the slaver ... who'd rough them up even more.
5) A slave may be bought by a noble, but only one per noble! A slave belonging to a noble basically becomes a personal hauler. Should the noble hunger, the slave would fetch the food; just as he'd fetch alcohol for a sober noble. They also keep the nobles' houses clean and, if the walls of a nobles' house aren't smoothed, the slave will smooth them instead of idling. However! Should a slave break the law, the noble will be held accountable and punished WITH the slave. The slave would still sleep in the designated 'slaves' quarters/barracks.
6) A slave will run away from ANY hostiles and will NEVER fight unless it is to save his own life. A slave will never, EVER risk death to save the life of a slaver. The only exception is if the hostiles enter the slaves' quarters, in which case the slaves might gang up on them.
7) Slave fertility is severely decreased ... but children being born into slavery will happen in a mixed population. Children born into slavery are less likely to rebel if conditions aren't too harsh - though the threat of a slave uprising should ALWAYS be there.
Reactions to slaves should vary. A free dwarf spotting a dwarven slave from another clan would get unhappy thoughts, especially if the slave would be in a bad shape. But slaves of other races might bring up mixed feelings. If the dwarves have had nothing but wars and bother from the Elves, seeing an Elven slave could bring up a happy thought - especially in fortresses populated with engravings of Elves striking down the Dwarves! But what if the dwarves and elves have co-existed, traded and even happily agreed to not cut down so and so many trees? An Elven slave might make the Dwarf sad. Those guys gave him the cloth which he made these fine pantaloons out of after all.
9) A slave's mood is usually glum - but can be raised via rewarding of good service. Clothes, food, alcohol or even promised freedom for them and/or their families/children could keep a slave from going berserk. Personal slaves to nobles get this effect nearly doubled, as a noble's prestige might demand that his slave would appear strong, healthy and efficient .. not a starved, beaten mess. Slaves might also be allowed to keep harmless pets, either as reward or from a kitten adopting a slave. Though one might argue that it's better to be feared by all, than loved by few..
Whew! And there's more!
Slavery should never be forced upon the player. In fact, the only way for a player to GET slaves would be if the player would actively seek it out; telling the soldiers to not kill the disabled, gathering the prisoners, returning them back to the fortress and then finally enslaving them. There'd be no situation where a player would find itself thinking, "Slaves? In MY Dwarven Fortress!?! It's likelier than I thought!"
Prolonged slavery should also heavily affect the way people percieve you. Some nations might frown upon it - even your trusted allies might become upset at this, even to the point of paying others to free your slaves. Then again, other nations with different views might suddenly greet you with open arms, applauding you and even defending you in slave-sparked wars! These feelings should grow more and more with prolonged slavery. A generation or two worth of human slavery would enrage free human kingdoms - maybe even to the point of declaring war, whereas other dwarven clans might simply shrug in apathy.
And again, with war come more possibilities - both for the player and the computer.
Let's say that you are a good guy and you're engaged in a defensive war against a neighbouring human kingdom. Those bastards saw your precious, precious silver mines and now want them for themselves! :cool:
Once religion enters, having slaves of religion A could cause members of that religion to feel wronged, while religion B might applaud it and even come to your aid in a slave war!
So!
Slavery.
Pros
+Cheap, efficient-ish workforce that's relatively easy to maintain.
+Slave trade can bring in mad cash.
+Slavery of certain peoples can bring you closer with certain allies.
+Slavery of certain peoples can make your dwarves happier.
+Slavery in general can make certain nobles very happy.
+Steady source of political intrigue and tensions.
Cons
-Nations that value freedom might view you with distaste.
-Victim nations, races and religions may be greatly angered.
-If your dwarves like the enslaved peoples, they might become upset as well.
-The more slaves you got, the more likely adventurers and such attempt to become liberators.
-Steady source of political intrigue and tensions.
Whew, alright. That's pretty much it. I might've missed a bunch of things, and there are probably typo's and bad grammar all over the place.. it's 1:30 in the morning. Oops.
I hope I got the point across, though!
Footnotes:
*I do this in my games and try to trade them to the Elves ... ALL the TIME. 10+ pieces of them are in a my stockpile in my current game.