RimWorld is a storytelling sandbox game about a group of far-future humans struggling to survive in a hostile alien world. And what kind of space dystopia would be complete without hostile raiders, killer robots, and carnivorous giant bugs? The recent Biotech expansion gave each of these aforementioned threats their own unique flavors you’ll have to contend with. You’ll need a strong defense to survive everything RimWorld throws at you. Luckily, we’ve put together this RimWorld defense guide to help you create the best defense setup and keep your settlement safe.
Let’s get started!
Preparing Your Base
We’ll kick off our RimWorld defense guide by discussing how to prepare your base for incoming raids. This includes advice on special fortifications, trap strategies, and ways to avoid raids in the first place.
Wealth Management & Diplomacy
The best raid defense by far is reducing the number of raiders that want to break into your base. Raid strength is based partly on how long you’ve been playing a particular settlement, but mostly on your current wealth. This mechanic is a great reminder to avoid stockpiling resources and overextending your base.
You can check your wealth at any time via the History tab. If things are looking too flush, look for ways to cut down on your excess goods. You can craft all fabric and rare metals into artwork or items your colonists can use or sell. You can also exchange resources whenever a bulk goods trader comes to town. Now those stacks and stacks of wood you have lying around won’t count against you when the game calculates how many grenade-wielding pigskin pirates to send your way.
Once you’ve become so wealthy that the trader can’t afford to take all your junk, you can start exporting crafted goods to nearby neutral settlements or outlander unions. You can’t reason with pirates, but the hostile pigskins from Biotech will gladly take resources off your hands.
If you can get your reputation with them to 0 or above, they’ll become neutral and stop raiding you. Improving your standings past 75 with your neighbors also lets you call them for aid in crucial moments. Try to keep them safe if they come to help or trade. Otherwise, they’ll consider your settlement dangerous and your reputation will be penalized.
When it comes to actually defending against raids, killboxes are an early essential. In the RimWorld community, “killbox” is the term for an area designed to corral raiders. Its maze-like design slows them down and groups them together before leaving them in a field of traps with no cover. They’re a must-have when making the best defense setup in RimWorld.
On your side of the killbox, you’ll have walls, barricades, and sandbags to give your colonists cover. Walls provide the best cover, but aren’t as easy to build into bunker structures since they only block shots from one direction. Just be sure to space them enough that your colonists can lean past them to shoot.
You can also use walls to funnel raiders into a particular area. Keep in mind they’ll always prefer to attack vents instead of doors, but will burst in through the front door if they have to. With that in mind, leave one section of your walls open, but keep it heavily reinforced. That way, any attackers lured to that area are forced to engage you at a disadvantage. Also, try to build your security layers such that colonists with short-range weapons can engage at the same time as those with long-range weapons.
There are two kinds of traps you can set that trigger when raiders walk over them. Spike traps, formerly called deadfall traps, are immensely helpful against early-game attacks from scaria-ridden animals. You can make them from wood, stone, or metal.
The best bang for your spike trap buck is to use wood versions at the front of your killbox. These will trigger first and kill smaller, weaker enemies, while also slowing down and injuring stronger ones. After that, make a layer or two of steel traps for more damage and armor penetration. These can stop pretty much anything that makes it past the wood traps.
While uranium and plasteel traps both do slightly more damage, these resources aren’t as renewable. Those are best used on other, higher-end security solutions.
Alternatively, later in the game and after a lot of research, you can build IED traps out of mortar shells. These explode as soon as someone walks over them, often killing the immediate target and doing a lot of damage to nearby targets. The type of damage depends on what kind of shells you use to build the device.
You can deal explosive damage and light fires with normal shells, disable mechs and shields with an EMP landmine, or annihilate absolutely everything with a couple of anti-grain warheads. IEDs also explode when shot, allowing for more elaborate traps that involve shooting an IED from a distance.
Just be careful not to lay traps down in 1×1 corridors or anywhere else that your colonists would be unable to avoid them. While every trap has a dodge chance, you don’t want to test that — colonists usually fail.
If you are going to make 1×1 corridors, you’ll need to create zones where your colonists are allowed to walk. Colonists and friendly animals will automatically walk around friendly traps, but there’s always a small chance of an accidental trigger. Both kinds of traps can be set to be automatically rebuilt after being triggered.
There are other ways to make the most of your killbox and keep your settlement defended. One such option is by using the environment itself. You’ll need walls surrounding any vulnerable part of your base, which is made easier if you build into a mountainside. You can also use water (whether it’s a river or a marsh) as a moat to slow down approaching raiders.
If raiders run into one of your buildings on the way to the fight, they might break it or light it on fire. The same applies to your crops and any animals in your pens. Keeping those vital food resources protected is an important priority in the early game. If you have spare wood and stone available, consider putting up some defensive walls around these areas.
The last thing to keep in mind is the pathfinding AI. Attacking enemies will always prioritize the quickest way to get their weapons in range of your colonists. When setting up your defenses, consider where the enemies are most likely to go and plan around it.
Speaking of mortar shells, let’s talk heavy artillery. While mortars are typically used offensively in history, our RimWorld defense guide will incorporate them into — what else? — your defense.
At some point, you’ll start to acquire “Reinforced Barrels,” letting you use those shells as more than just traps. Reinforced barrels cannot be crafted, only traded for and looted from raiders or quests.
Colonists can load mortars with shells of varying effects. Be careful, though — shells can drift off target depending on a colonist’s shooting skill, and may cause collateral damage. Additionally, shells always run a risk of igniting and exploding the whole stack at once, decimating the area. After twenty shots, you’ll also need to refresh the barrel of the mortar with a new one.
More conventional defensive artillery exists in the form of turrets. These are incredibly valuable for keeping the borders of your map defended.
Early on in the tech tree, you can unlock mini-turrets. These have a gun equivalent to the LMG and can take on most soft, early targets like animals and raiders. You can build them with small amounts of harder metals (like uranium or plasteel) to give them more hit points. Occasionally you’ll need to use some steel to refresh the barrel.
Further down the tech tree, you can also build an autocannon. Autocannons fire bigger shots much further away, but have a minimum range where they can’t hit anything at all. Uranium slug turrets have an even longer range but only fires single shots. The slug turret can outrange its preferred target, mechanoids, but does need to be reloaded with more uranium sometimes.
Finally, the newest addition to the array of turrets is the rocket-swarm launcher. These require activation mid-combat and deal a lot of damage to a small area. The rocket-swarm launcher should only be used against groups of raiders, since it won’t do much damage to armored mechanoids.
All turrets can explode when damaged too heavily, so it’s good to build them separate from your colonists’ defensive line. You should also add some barricades or sandbags around the turrets themselves to provide them with cover from enemy shots.
We’ll cover mechanoid enemies a little later on in our RimWorld defense guide, but let’s briefly touch on friendlies. You can craft and animate your own mechanoids once you acquire a mechanitor uplink. Unsurprisingly, largely self-sufficient mechanic guards are a great choice for defense in RimWorld.
Early on, basic millitor units can be used as front-line fighters to soak up damage and take out low-level targets. Any fighting mechs that die in combat can easily be revived by the mechanitor.
You’ll eventually be able to craft the other fighters that the mechanoids regularly send your way. These include pikemen and lancers for sniping, as well as scythers for close-range damage. If you’re willing to take on mechanoids multiple times, you can even construct the bosses like the Diabolus mech.
Mechanoids create toxic waste packs when charging or gestating during their creation. You’ll need to dispose of these, otherwise they’ll taint the terrain around you. You can plant polux trees to gradually purge an area of the contamination from the toxic waste, but may not be able to keep up with your demands. Cold storage areas keep waste packs on ice and prevent their decay, but take a lot of electricity and space. After defeating all three mech bosses, you will unlock an atomizer that can dispose of the waste for you.
In the meantime, in order to keep your waste storage from filling up, you can load up drop pods with toxic waste and fire them into the sky! Be wary of exactly where you send them, since nearby factions will be enraged by you polluting their home. Hostile factions might even send raids in response. This, of course, can be a way to taunt someone into attacking you if you’re ready to take some prisoners.
The Ideoligion DLC adds a few helpful ways to defend your base, too. First and foremost, your colonists’ beliefs can influence the defenses you have available.
A group of tribal people who love animals will have a better time training local predatory animals than using automated defenses. Bears, wolves, and wargs are great options if you have Inspired Taming or are just a very effective Beastmaster. Tunnelers are better at building the classic RimWorld mountain base and don’t take the usual mood debuff from spending too much time indoors. This lets you hunker down as long as you want. Supremacist and raider factions can build skull spikes and ignore the mood debuff from seeing corpses.
Transhumanists are among the most powerful additions to the Ideology DLC. They can elect a research specialist to help them rush through the technology tree and gain a happiness bonus from having bionic parts installed. They also unlock numerous buildings that strengthen individuals at the expense of food or energy.
Gauranlen Trees & Dryads
The Ideology expansion also added Gauranlen trees and associated creatures called dryads. “Gauranlen Sprout” events let you harvest a seed to plant a Gauranlen tree. These trees need to psychically connect with a human host. From there, you’ll be able to prune the tree to maintain a connection. The higher the connection, the more dryads it will spawn.
Some of the dryads are great utility pets, growing medicine, berries, or wood on their backs. The fighters, however, are main reason we bring them up in our RimWorld defense guide. Barkskin dryads can absorb a lot of shots, so you can send them into combat to tie up opposing melee troops. They move slowly and will typically gather around the Gauranlen tree that they’re connected to. Clawer focus more on dealing damage than soaking it up. You can use them as shock troops to do a lot of damage to the front-line forces of a raid.
The disadvantage of dryads is that they’re very flammable (on account of being, y’know, plants). They can also take a little too long to get to the fight if their tree isn’t close to the front lines. And, if you don’t have anyone specialized in plants, pruning the tree is often not worth the time it takes to get your dryad guardians.
Equipping Your Colonists
In RimWorld, the best defense setup means nothing if you don’t have the troops to back it up. Next up on our RimWorld defense guide are the colonists themselves. Equipping them with the best gear, items, and traits will help you take down any raids that come your way.
In the Crashlanded scenario, you drop in with three weapons — one for each of your settlers. Your best shooter to take the hunting rifle, while the second should take the revolver for some close-range backup. Give your best melee fighter the plasteel knife. Outside of that, a lot of your early-game weapons are just going to be whatever you can get ahold of.
Once you’ve done enough research and acquired enough resources to start making your own weapons, you should try to gradually transition everyone to using a heavy SMG or an assault rifle. Brawlers and melee fighters should get longswords, spears, and war hammers. Blunt weapons are less likely to outright kill their targets than any kind of sharp damage. If you like taking lots of prisoners, prioritize making war hammers for your close-up crew.
Via quests and searching ancient ruins, you’ll eventually gain access to incredibly powerful persona weapons. These can provide you with a unique bonus or penalty, depending on the weapon.
Pairing your best weapons with those who can use them the best is key for your defense strategy. Be sure to check your soldier’s traits before you assign weapons and armor. Low shooting skill can actually make your colonists dangerous back-range backup, as it increases the chances of friendly fire.
Brawlers take a mood debuff from holding ranged weapons, but are usually strong and passionate about melee combat. Tough colonists make good front-line soldiers. You can balance the tradeoffs of “careful shooters” by giving them weapons that already take a long time to fire, like sniper rifles or charge lances. Likewise, give “trigger-happy” colonists weapons that fire rapidly, like the heavy SMG or the chaingun.
Unsurprisingly, armor is a crucial part of a good defense in RimWorld. It takes quite a bit of research to build an optimal set of gear, but there are a handful of ways to get armor in the meantime.
First up is crafting. You can protect colonists relatively well with just heavy leather outerwear. Dusters are best for hotter environments, while jackets and parkas are best for colder ones. Devilstrand is the best renewable clothing fiber in the game, but takes a very long time to grow. High-quality devilstrand clothing can actually provide more protection than average-quality metal armor, and your colonists can still wear a flak vest over it to protect their most vital organs.
Looting is another option. You can loot clothing off downed raiders, but dead ones taint everything they die wearing. Any settlers that are not Cannibals will be unhappy wearing clothes that someone else died in, including armor. If you’re lucky, you can get perfectly good armor by stripping downed raiders before taking them prisoner or letting them bleed out on the battlefield.
You can also trade for armor, though it comes at a steep price. Since it’s difficult to keep the base materials around for high-level armor, however, this is a good option if you’re looking to spend some silver.
At first, any heavier armor you receive will likely be via quest rewards. Power armor encompasses recon armor, marine armor, cataphract armor, and a specialized variant of each that comes with utilitarian abilities like fire-bolt launchers or integrated jetpacks.
The latter options all slow your movement quite a bit, but make up for it with incredible protection. Each has a corresponding helmet that has fewer drawbacks, so if you need to pick, you should prioritize the helmets. A single headshot could be career- or life-ending for the unguarded skull of an unwary space settler!
Beyond weapons and armor, you can also access utility items that can have a big impact on combat. Many control positioning or generate cover of some kind, which will drastically improve your defense in RimWorld. Colonists will automatically equip any compatible utilities in their apparel menu.
One of the best utilities is the shield belt, which generates a force field around your colonists. This shield has hit points depending on the quality of the belt, and can block bullets, pulse shots, and explosions. Keep in mind that you can’t fire out of a shield belt, so you’ll need to make a separate set of apparel permissions for your melee fighters, all of which should get shield belts as soon as possible.
Another option for close-range fighters is a jump pack that lets them use some chemfuel to rapidly advance across the map. Jump packs gets your heavily-armored melee fighters directly into the fight to tie up the longest-range enemy raiders. Smokepop packs are another chemfuel item, this time providing defensive cover by making a cloud of smoke around your colonists. The smoke also blocks enemy turrets from locking onto them entirely.
There are also numerous uncraftable, single-use items that only come with a few charges. Psychic insanity lances, for example, can send one target into a berserk rage. If you pick the right target, like someone carrying explosives or leading the pack of melee fighters, you can turn the tide with just one item charge. Try to save these for crucial moments.
Items aren’t just for offense, either! You should equip all your non-combat colonists with fire foam packs to help them extinguish fires faster. The forces of nature are arguably the greatest threat to your base, and you unfortunately can’t shoot a fire to death.
The Royalty DLC expanded defense options far beyond the simple turret-laced killbox of vanilla RimWorld. Colonists promoted to royalty gain psychic abilities in exchange for their newfound prestigious expectations. Many of these powers can be very useful in defending a base.
The powers you receive are random, but you can acquire more by trading for psy-trainers of an appropriate psylink level. You can upgrade your colonists’ psylink level with items called psylink neuroformers, or by getting them promoted within the imperial hierarchy. You can also make abilities themselves more powerful with eltex clothing or prestige power armor.
At first, you’ll be limited to lesser abilities, like momentarily stunning someone from a distance. Few powers are outwardly offensive at the lower levels, and are more useful from a support standpoint. Don’t underestimate the value of support, though! Skip is a relatively low-level power that can have a huge impact on combat, as it allows you to teleport both friendlies and enemies on the battlefield. This lets you rescue valuable allies, or drop an enemy directly on top of one of your traps.
The best candidates for becoming a psycaster are already good at fighting in some other way, and ideally have high psychic sensitivity. This decreases the cost and increases the power of their abilities. For the sake of our RimWorld defense guide, we strongly recommend having at least one good psycaster around.
The Biotech expansion introduces the ability to modify the genes of your colonists. You can probably already see why we’ve included it in our RimWorld defense guide!
Players can design their own xenotypes at the start of the game. These xenotypes may appear at random among other factions or with new recruits. The addition of babies and pregnancy mechanics also allows you to pass down these genes to make new hybrids.
This is important, as most xenogenes aren’t passed down. Once you’ve built a gene assembler and extractor, however, you can make xenogenetic packs. These can be implanted into your colonists to add new features to their bodies. This allows you to specialize the genetics of each colonist to fill specific roles or keep up with the demands of your environment. You can also collect xenogenetic packs from traders or by extracting genes from your colonists or prisoners.
Many of the game’s default xenotypes never pass down their genes via germlines. This includes Hussars, which are powerful, red-eyed supersoldiers engineered to fight (and do little else). Getting ahold of a hussar can be tough, but they make excellent shock troops for base defense or launching preemptive assaults on enemies.
Of all the xenotypes, the one that makes the biggest difference in combat is the Sanguophage. These space vampires are effectively immortal, as they can’t be killed unless their brain is destroyed. Small defects, like missing fingers or damaged eyes, will heal on their own. They get a huge bonus to melee combat, and since they’re nearly unkillable this makes them into fantastic front-line fighters. They can also hand down their xenogenes to an apprentice every few years, eventually allowing you to build a small army.
Sanguophages get access to a huge range of specialized skills, including the ability to leap across the battlefield and heal their allies’ wounds. They can also fire a piercing spine at enemy targets from a fairly close range. The spine can usually down a human target, but it does cost quite a bit of hemogen.
Speaking of hemogen, keeping a Sanguophage around forces you to adopt a more aggressive playstyle to help manage their thirst for blood. They can feed off colonists and prisoners, though this comes with a self-explanatory mood debuff. It’s better to find ways around it where you can. Extracting hemogen packs from prisoners upsets them less, though you will need a Doctor to perform the procedure. You can also change your ideoligion so your colonists worship their vampire overlord, removing the debuff from being fed on. Another general requirement is a deathrest room, where your Sanguophage can climb into a mechanized coffin for a few days to recharge.
Taking on Raids
The last piece of our RimWorld defense guide covers the raids themselves. The Biotech expansion adds unique mechanics to watch out for in the different types of raids. Any raid can potentially bring down your base — even successfully repelling the attack might result in defeat if the costs are too great. You need to be ready for anything. Luckily, our RimWorld defense guide has you covered.
Raider Attacks & Behavior
At first, raiders will appear in small groups and generally wait outside your base for a while before attacking. They may sometimes attack right away or appear from multiple angles, though, so stay vigilant. The gear of the raiders varies, with higher-level raids spawning attackers that have more powerful equipment and tougher armor.
Before long, you will get letters that tell you the raiders are “unusually clever in their tactics.” This means they’re going to dodge your traps and try to avoid your turrets. If you’ve designed your killbox well, they won’t have any choice but to walk right into your defenses, but these kinds of raiders are definitely smarter in their pathfinding and will test the limits of your walls.
Some raiders will even come with breach axes and explosives to try to break through your walls at their weakest points. Others will drop in via drop pods and break through the roof of your building. Others still will be scattered haphazardly and unpredictably across the entire map.
On occasion, you’ll have to deal with sieges. Some raiders may drop in with a lot of siege equipment and build a small fort on the outskirts of your territory. They’ll assault from a distance using this fort as a base. That said, siege events often drop attackers in locations where they’re incapable of fully building their siege camp. This lets you take the resources they were going to use for yourself. If you can ambush the siege party before it can set up, you may even be rewarded with a big pile of artillery shells.
Infestations & Insect Hives
Now it’s time to talk about Rimworld infestation defense. While mountain bases are generally a great, naturally defensive choice, they do come with a distinct downside — Insect Hives. These hives spawn insects that tunnel up through the floor of any area that can’t be bombarded by outsiders. Consider it your punishment for retreating to the safety of the mountains.
Hives spawn insects, which in turn spawn more hives, so you’ll have to go on the offensive to keep them in check. Spawns happen during an infestation event, or at random when using the deep drill or exploring ancient dangers. With the Biotech DLC, they may also spawn when too much pollution accumulates around your base.
Warmth and darkness are two major deciding factors in whether or not an infestation will occur. Infestations won’t happen in rooms that are too light or too cold. If you go below -17C/1.4F, insects cannot spawn. That’s good news for all that toxic waste in your cold storage rooms!
There are three kinds of insects: megascarabs, spelopedes, and megaspiders. Megaspiders are the most dangerous by far, but the others can still cause a lot of damage if they get too close.
Insects are always close-range fighters, and they don’t have very strong armor penetration on any of their abilities. They do have strong armor themselves, so focusing on armor-breaking weapons will be important for taking them down.
Insects can actually be tamed, but given that they’re usually hostile, this can be very difficult. Once downed, a colonist with high medical and animal skills can tend to the megaspider. This creates a small chance that the insect will bond with that colonist. Failing that, you can hope one of your colonists gets Inspired Taming, allowing them to tame an insect with no chance of failure.
Mechanoids are intelligent machines that have gone rogue, and are one of the most problematic threats in the late game. Their presence is expanded greatly by both the Royalty and Biotech DLCs. Royalty added numerous buildings they can drop with when attacking, and Biotech added three increasingly difficult boss fights you can engage with. Thankfully, the reward for these boss fights is the ability to unlock increasingly more powerful mechanoids for yourself.
Mechanoids immune to a lot of tactics designed around fleshier enemies, so you’ll need to reconsider tactics. For starters, they’re almost completely immune to fire damage, and have much higher armor against blunt or sharp damage. They also don’t feel pain, so simply doing damage isn’t enough to get them to tap out. You’ll need to destroy enough of their internal components that they physically can’t keep fighting you. Lastly, many of them carry weapons that will outrange your colonists, forcing you out of your bunkers.
Luckily, since mechanoids are built with brain scans of living humans, they’re still vulnerable to psychic powers and lance charges. EMP weapons can also short out their systems and give you time to get close. Keep in mind that EMP weapons only work for a short time, after which the mechanoids will adapt to the effect for a while.
Oftentimes, the mecha force will arrive and go to sleep until you get within a certain radius of them or engage them from afar. This can give you an opportunity to set EMP traps in a circle all around their landing point.
Join the High Ground
Raids are ultimately the biggest test of your settlement’s merits, but we hope our RimWorld defense guide helps plan your setup and strategy. After all, a thriving community that can’t defend itself isn’t really thriving at all. If you have any questions or suggested strategies let us know in the comments below! Be sure to subscribe to our newsletter fro more content on RimWorld and your other favorite games.