Wait, raiders? But I did pirates and bandits.
For the sake of clarity, I’m using raiders to mean those who predate not by ambush or chasing down victims as they travel, but by attacking stationary settlements whose defenses they think they can overcome, striking from outside before slipping swiftly away with whatever they can carry. There may well be some overlap between these groups, especially in times of famine or if pirates feel emboldened to attack ports outright, and in such cases the details will likely be a blend of what is presented there and what is presented here.
Raiders are a common threat for adventuring parties, attacking their home towns, places where their friends or allies dwell, common folk the heroes feel obligated to protect, or simply those that the authorities will pay sellswords to protect. These threats may take the form of goblinoids pillaging farming villages, vikings sacking a coastal monastery, cultists from beneath the earth taking the supplies they need to continue their strange rites, and more. Raiders usually seek a combination of supplies (including rations, food, spare weapons and so on) and what coin and treasure they can lay hand upon. They may be unlikely to actively seek captives, but depending on their needs they desire captives even more than other plunder.
Reasons for Raiders to take Captives
Laborers. Stereotypically, fantasy raiding cultures raid either because they cannot establish self-sustaining infrastructure on their own in the regions where they dwell (wastelands with little food or populations insufficient to undertake the kinds of projects needed while still sustaining themselves), because they are temperamentally, culturally, or religiously resistant to doing so themselves for any cause other than war (Warhammer orcs, cultists of gods of tyranny, and the like), because the task is too great and they are already pressing their entire population into service (constructing a 100-mile wide doom-gate to free their otherworldly masters) or simply because it is easier for them to make others do the work.
Encumbrance. A swift raiding force seeking to take back huge quantities of resources, say to supply an army, will likely not have enough capacity to carry back everything they need to obtain, and will press the folk they are raiding into service hauling huge sacks of grain towards their army’s supply train or the like, along with any animals that can be loaded up and brought along for the task.
Thinning Resistance. Simply put, each captive taken now is one less pair of hands to take up a spear the next time they raid the area. Raiders who cannot range widely and must attack the same communities repeatedly will want to do what they can to reduce the defensive capabilities of the settlements without leaving them so desolate that the survivors give up and flee the area rather than continuing to produce more resources.
Cult Purposes. Cults probably have a low success rate of brainwashing people they have captured, but in the wilderness that’s more new blood than they would be able to bring into the fold otherwise. And those they cannot persuade can always be put to work or saved for when a dark ritual is to be performed.
Slave Trade. If there are neighboring civilizations that are willing to buy slaves taken captive in battles (or without asking questions), the gold from selling the people of a hapless town might equip the villains more readily than everything in the blacksmith’s shop and all the coin and food in the settlement combined.
Raider Capture Tactics
Surrender. The simplest way raiders take captives is if they soundly defeat the settlement’s defenses and march the survivors away at sword-point after ordering them to tie their own hands. Even if they do not completely conquer the township, many of those unfit to fight or caught without a weapon will surrender rather than face a pack of well-equipped enemies with their bare hands.
Divide and Conquer. Canny raiders might wait until most of the strong folk of a hamlet have traveled out into the farms or are minding herds of beasts far afield before striking the core of the settlement. They might wait until the middle of a work shift to attack a mining town, trapping half of the village underground until they agree to surrender. They may even launch a diversionary battle to draw the defenses off before attacking from the other side.
Speed. Mounted raiders who are not equipped to directly confront defense forces will rely on strike-and-fade tactics, grabbing whomever and whatever they can and fleeing before a response can be mounted, then relying on fatigue from continual vigilance to weaken the defenses before striking and running away again.
Traps. Raiders likely will not be able to trap the village itself, but if they are stealthy they may be able to set snares, pitfalls, and the like in an area where they can later bait the defenders of the town to pursue them into. This is the tactic of choice of kobold raiders striking at gnomish or dwarven settlements especially. With some magical backup, cult raiders might be able to place glyphs and illusions, as well as seize control of the minds of key individuals before fleeing back behind the trapped perimeter.
Exotic Beasts. Some raiders may have access to some sort of monstrous animal they utilize in their pillaging. This may be giant spiders who can fling or lay webs, large packs of trained wolves, giant wasps with poison that subdues rather than kills, or simply big, threatening creatures like dinosaurs, terror birds, or trained big cats.
Escaping from Raiders
Joining. Depending on the nature of their forces, the easiest way to be free of raider captivity is to simply join their raiding parties. Many raiders are desperate sorts who want every numeric advantage they can get. If you can convince them you are serious, you can probably become part of their force.
Stealth. It is likely that an especially prosperous raiding party will have a much larger number of captives than guards, and will rely on threat of force and superior mobility to enforce order. If you can slip away quietly, they may not even notice anyone is missing from the small crowd they are marching across the steppes.
Slowing Them Down. If you know—or if the raiders believe—that rescuers are hot on their tails, then sabotaging travel progress can either delay them until the cavalry arrives or until they decide to cut their losses and escape without their slow-moving captives. If this can be done via subterfuge, it minimizes the risk of the raiders becoming agitated with the captives and retaliating.
Force. If the raiders took a beating during their attack and the captives can get the jump on them at an opportune moment, it may well be possible to defeat them in a second battle and march home victorious. Even if you can only defeat their most mobile soldiers, a rebellion may make other avenues of escape viable in the immediate aftermath.
What’s in it for the Party?
Gratitude. The villagers you help to escape and be reunited with their families will likely move heaven and earth to assist you in the future. Even if the party are the only captives, if you take down some of the scourge threatening their livelihood and peace on your way out, or bring back some of their valued possessions, they will be thankful. If the raiders were a serious threat and you manage to rout them, there might even be some military honors in it for you if you play your cards right.
Siege. If raider are pillaging vulnerable communities to keep a steady supply of food and slave labor for some grander effort, cutting those supply lines—even temporarily—can weaken the villains’ plans and stall their efforts. It may even force an army they are supplying to slow or retreat to avoid starvation.
Bounties. Any place with a raider problem that also has coin to spare will likely have a standing bounty for every raider stopped. Just ask the road patrols or sheriff about it. Even if you can’t defeat them, providing the king’s patrols with information regarding the raiders’ locations and plans will usually merit some kind of compensation.
Quality Gear. Raiders almost certainly possess superior equipment than the areas they prey upon, or they would already have been repelled regularly and left to seek weaker prey. Far more gear passes through their hands than they themselves need, and they will probably be trading up at every opportunity in order to maintain their tactical advantage.