10/24/2014: 10 Leader Guides are undone, but the rest of the guide is 95%+ complete. I will work on this eventually but have my hands full playing Civilization: Beyond Earth and writing for The Sims 4. There is a possibiliy I will try to cover at least some of the gameplay elements from Beyond Earth, but can't make any promises. If you'd like to say thanks, you can use the donate button or use EA Origin, Gamestop, or Walmart to make a game purchase.
Civilization 5 Barbarians Guide
Conquering Encampments and Preventing Barbarian Invasions
Unless you specifically turn them off when setting up your game, Barbarians will appear in every game of Civilization 5. This Guide will teach you about where Barbarians will spawn, how they function, and how you can best deal with (and prevent) Barbarians invading your lands. Barbs are a problem of the early-game, as your Civilization has not yet grown and you will not have many military units to deal with them. You must advance and build units to protect your people from their raids, particularly on higher difficulties, as they will attack more often.
Barbarians spawn from Encampments, and will periodically do so until those encampments are destroyed. New encampments may spawn in any place that is not visible by your or another Civ's units. With this in mind, you are able to prevent new encampments from spawning on the outskirts of your lands by parking units to extend your view beyond your borders (hills are good for this). Doing so, you may entirely prevent them from spreading on your continent, or at least near your own lands. This is commonly referred to as Sight Blocking.
It is a common strategy in the early-game to position a unit near the area you want to settle to prevent any new encampments from spawning between your City and the destination of your Settler. This can allow a Settler to go and found a City without an escort in certain situations, but realize that Barbarians can use horses and may appear out of nowhere to capture your Settler.
Encampments are almost always guarded by a unit, unless that unit has stepped out to attack something vulnerable. They typically will not attack from the encampment unless there is a clear advantage, such as your unit being wounded with another Barbarian nearby to help. If they attacked, they would give up their fortification bonus. You will not usually be able to wipe out an encampment in a single attack unless you are using a very powerful unit. Barbarians don't heal, so when your unit starts to get beat down you may skip a turn or two and wait on your unit to heal up before attacking again. When you clear an encampment, you'll get 25 gold (a little more on the lowest difficulties). This can help you afford to buy units and buildings in Cities, while also stopping new Barbarians from spawning.
Barbarian Encampments will occasionally spawn new units, based on the technology level of the most advanced Civilization in the game. This can work for or against you, but the AI has a bigger attack bonus vs Barbarians than you do - presumably to compensate for their occasional stupidity. These units will usually attack the nearest City, which will give you an idea on what encampments should take priority. Encampments on the coast may spawn ships, which can be a major pain when you have sea trade routes.
When Barbarians come to your lands, they will often simply pillage tiles. You must protect your Workers from these attacks as a City will not be able to kill a Barbarian in a single attack. Barbarians also try to prioritize capturing your civilian units like Workers and Settlers. Keep in mind that you do not need to make your Workers flee to your City for safety right away - sometimes they are on the opposite side of your lands and have the same movement and penalties (crossing rivers) as your own units.
If two or more Barbarians come within range of a City, they may actually attack it. They will not often be able to really take over the City unless it's really poorly defended, for example low population, no unit to protect it and the Barbarians have advanced to higher level units. Otherwise, you should expect Barbarians to continually walk to new tiles and pillage them. This results in the Barbarian being healed and makes them take longer to kill. This is why it's wise to protect border Cities with at least one unit (War aside).
One unit is usually enough to protect your City unless multiple Barbarians come knocking, which is not often. You can use the Zone of Control to protect your Workers from a Barbarian attack to let them finish their job. If a unit stands between the Barbarian and a Worker, it will not be able to go around your unit, consuming its moves in one turn and being more likely to attack your unit than going after the Worker. Thankfully, Workers will automatically wake up if a Barbarian comes nearby, giving you the option of moving them from the tile. Any tile improvement construction in progress is saved (realistic) so you can go back and finish the job when they're dealt with.
Barbarians that have captured Workers or Settlers will escort them back to a nearby encampment. You will occasionally find the Workers or Settlers of other Civs in these camps. Attacking and freeing these Civilians will give you a few options - you may return the unit, resulting in either a diplomatic boost with a Civ or influence with a City-State, or take it as your own. Settlers from other Civs will be converted to Workers when you elect to keep them. There is no penalty for keeping them, so never return a Settler to another Civ unless you do not care that they expand! Freeing Workers, on the other hand, can be a great help toward getting a Declaration of Friendship with another Civ in the earl game.
Going after the Barbarians
On all difficulties but Deity, you will gain a Combat Bonus vs Barbarians, making them easier to kill than the units of other Civs. For a few reasons, you will usually want a ranged unit like the Archer when attacking Barbarians - even better with a melee escort. As I've said, they will not attack from the encampment. It is usually safe unless a fresh Barbarian unit spawns and gives your Archers valuable experience toward Promotions that can greatly enhance their ability to protect your Civ or go on the offensive against others. Be careful on firing the last shot with other Civs' units nearby, for a Scout could come and clear the encampment as your Archer will need another turn to step in and finish the job. Warriors are fine for bringing down early encampments, but suffer against Barbarian Spearmen and stronger units, while also needing to heal in between attacks on upper difficulties. A fortified Barbarian still gains a big combat bonus and your bonus vs Barbarians dwindles the higher the difficulty is raised. Thus, ranged are better than melee, but a combination is best to ensure you get the last hit and get to clear the encampment on the turn the guard dies.
A Scout that has been promoted to an Archer is the best unit to use. Horsemen are also great, for they have excellent mobility and can faster cross the map to get to an encampment. They are also very helpful in responding to attacks in your own lands.
Protecting Land & Sea Trade Routes
Use sight blocking to protect your land trade routes from Barbarians and be proactive about attacking any encampments near that trade route. Losing a caravan is a pain and a setback to your Civilization's progress. It will certainly harm your gold per turn and may also affect Science output. Protecting land trade routes is fairly easy, but those at sea are more prone to attack. If you're going this route, a lone naval unit is not enough as sea trade routes can go quite far. To prevent these attacks when you have access to the land between, attack those encampments on the coast to stop them spawning and occasionally scout for any new threats. You can use Triremes to sight block along the coast, but they may not attack the encampment - only ships that spawn from it.
Using Barbarians to Help your Civ
Fighting Barbarians will allow your units to gain up to the first two levels of experience. Thus, a unit coming out of a Barracks could gain only one level from fighting Barbarians. This is to prevent abuse of them to create super units, but makes sense as well as they would not have knowledge of tactics like a trained unit from a Civilized nation. Still, these first two levels are very helpful early in the game. You could gain Drill I/II or Shock I/II to get closer to archers with two attacks, bonuses vs Cities or ranged defense. It is wise to use newer units to go get these levels, rather than a unit that has already gained these levels. Units that have received these two promotions are much better at fending off attacks or attacking other Civilizations.
Adopting the Honor Social Policy will let your Civ get Culture from Barbarian kills, relative to the strength of the unit killed. This is particularly potent when you are playing the Aztec, who already get Culture from killing enemy units. Sometimes, adopting Honor can result in a net gain and is absolutely worth it even if you do not intend to finish that tree - for you can make it up with Culture from kills, particulary with Raging Barbarians turned on. Additionally, Honor will grant a larger combat bonus vs Barbarians and also inform you when new Encampments spawn nearby, which lets your units respond right away.
However, you may not want to respond right away to an encampment you've discovered. I often leave them alone a while in the early-game. City-States will nearly always offer a quest to attack a nearby encampment (and sometimes quite far away). This can give you valuable influence with them, and allow you to gain alliances early in the game, particularly when you finish other City-State Quests. Waiting to clear an encampment until the nearby City-State has offered a quest is a solid strategy in most situations. You can even beat it down to half or so, such that another Civ's Scout wouldn't attack it but you can finish quickly when the quest is offered. Killing a Barbarian within the lands or right next to a City-State's borders will result in a gain of Influence with that CS. Sometimes, they will offer a quest just to kill units attacking them, which can sometimes let you accomplish two Quests - particularly if the encampment is right on the City-State's borders.
In other situations, you will want to clear the encampment as soon as possible to ensure the safety of your Workers and prevent them from pillaging your tile improvements, which slows down your Workers and has a negative impact on a City's production/food output, etc.
When setting up your game, you may turn on the Raging Barbarians option. This will increase the spawn rate from encampments and may actually make the game much more difficult, particularly if you are unlucky and have many units come attacking you at once. This option can also be used to your advantage if you have a strong military, for your units will be better-trained and ultimately present a bigger threat to other Civs. Certain Civs will do very well with this, such as the Ottomans (for capturing ships), Aztec (culture from kills), or any Civ that adopts Honor.
Share your Tips for dealing with Barbarians in Civilization 5 using the form below.
I usually left the barbs encampments to generate barbarians. Once I trained new military units, I immediately go to the barb encampments, and start attacking those strolling barbarians with the intention of raising my military units' experience.But I left the encampment untouched.
And I also notice that if you are the one who discover the encampment (not the city states, given as a quest to be dispersed) the city-states will not immediately ask you to destroy the encampment. If you do, aside from pillaged gold and experience, you gain no influence to the city-states nearby the barb encampment. It is better to just let the encampments generate more barbarians until the city-states give you quest to stop the barbarians attacking their borders. It is an act of exploiting the situation, for INFLUENCE, GOLD, and EXPERIENCE. Nevertheless, just hope that those strolling barbs will not reach your BORDERS. :)
I mean, in a normal (prince) difficulty mode..
They can be total jerks and it's often assumed they like to pick on the player more than the AI. I have seen them act fair, and other times it seems they want to go for me even though there's a better target. Barbarians have an attack range based on difficulty, so the higher the difficulty, the more eligible your Cities are to attack from multiple attacks. It's best to deal with those further from City-States first, as they're less likely to be chosen as the target of a Quest. If a camp is closest to you, you can be sure you'll be seeing some activity. Sometime's it's hard to gauge which is closest - you or another Civ/CS, but they are likely to choose randomly so long as both are within their range.
BTW, this odd behavior can happen with uprisings within other Civs over Ideology too. The barbarians spawned from those have pillaged my tiles in a puppeted City nearby, forcing me to defend it...