Factions

Faction Types

There are three main types of factions on the planet:

Tribes

The tribes are groups of neolithic people with basic weaponry such as bows and spears. They have probably inhabited the planet for a long time. They always wear tribal clothing, which is equivalent in stats to a standard shirt. People from this faction are usually very hard to recruit (difficulty 80+), though it is possible to do so. Tribe names often have words derived from Spanish, such as 'miñoca', 'legua', etc. They may not seem very strong due to their low level of technology, but they make up for it with sheer numbers. It is not uncommon to see raids of over twenty tribesmen later in the game, even on lower difficulties. This faction is a formidable ally and foe alike. They may not be as dangerous as pirates, but they are not insignificant.

Outlanders

Outlanders use the same equipment and technology as pirates, but do not behave the same. Outlanders by default are non-hostile but can be provoked into hostility. Due to their similarity to your colony they can be considered the standard faction. They often use similar equipment and tactics as normal pirates, but rarely use high level gear such as charge rifles or snipers. Be nice to them and you will be rewarded, but anger them and you basically have another pirate group, except this one can be negotiated with.

Pirates

Pirates sport modern weapons and gear, though occasionally use advanced gear. It is pretty much impossible to negotiate with them (any attempts to do so result in vitriolic insults being thrown at you over the comm system). Pirates are the primary source of raids, usually attacking from the sides and occasionally dropping directly on your base. They kidnap incapacitated colonists if you leave them incapacitated and within reach. The Pirates can be considered the bad guys of RimWorld.

In addition to the above, there are a few off-map factions;

Mechanoids

Main article: Mechanoid

The Mechanoids are a faction of super-advanced robots, all of which are extremely formidable in combat. They come in two forms: Centipedes, and Scythers.

Centipedes are the Mechanoids' heavy infantry unit, coming equipped with a minigun, inferno cannon, or heavy charge blaster, as well as remarkably tough armor. Centipedes are capable of dealing a great amount of damage to your colony. Their primary purpose is to soak up damage from static defenses while suppressing enemy infantry's movements. They cannot move quickly, so it is often possible to run around it in circles and not get injured. Use this to your advantage when combating Centipedes.
Scythers are the Mechanoids' light infantry unit, coming equipped with a charge lance and lighter, though still durable, armor. Scythers can deal a great amount of damage per shot with their heavy weapon, and their range means that they can attack improvised turrets without retaliation. Their primary purpose is to pick off defenses and defenders, while maintaining enough mobility to chase down survivors. If at all possible, it is best to avoid engaging Scythers head on, as their weapon can do significant and possibly lethal damage in the first shot.

Once killed, all Mechanoids leave a mechanoid corpse which can be broken down at a machining table for even more metal. A Mechanoid attack can easily destroy your colony if you are not prepared for it. They have a decent combat AI that utilizes each unit's strengths, making them a dangerous enemy to face. Mechanoids can invade from the edge of the map, or they can be dropped directly into an unsuspecting base. Mechanoids are the enemies of the "Ancient Ship Crash" event, in which they will emerge from the wreckage of their ship and attack if a colonist attacks it.

Spacers

Spacers are an off-map faction, similar to mechanoids. They are encountered during escape pod events and within ancient ruins. When they crash in from space, they often require medical attention. Spacers can also often be found within the cryptosleep caskets inside ancient ruins. No one knows what scenario forced them into their prolonged sleep, but those daring enough to awaken them should be prepared to defend themselves from an attack as the spacers sometimes lash out in dazed confusion. Sleeping Spacers often wield high-tech weaponry and powerful armor, but Spacers typically have low recruitment difficulty. Managing to subdue them will quickly gain skilled colonists.

Insects

Insects only spawn continually when the Infestation event occurs. They may be found in opened Ancient structures. Megascarabs may be found in desert biomes.

Faction bases

Factions have many bases generated when the world is created, which can be traveled to by forming a caravan or launching drop pods. If you send a caravan or drop pods to neutral or friendly factions it will initiate a trade. However, if you send it to a hostile faction you will start an assault on that base, which can be destroyed once the enemy flees. Then you have 24 hours to collect all the items you want before a caravan is automatically created to leave.

Faction Relationships

In Rimworld, one of the key gameplay features is the raids by enemy factions. When a new world is generated, various factions within the world are also added. These factions have varying relationships with your colony, and all of them may be your enemy from the start. As time progresses and your colony accumulates more wealth and grows larger, it may be a good idea to attempt to improve these relationships to even eventually have an ally to call upon in the worst of times.

Improving Relations

There are multiple ways to boost relations with an ally or enemy.

The easiest, though more expensive, method of doing this is to contact them on the comms console and give them 300 silver for +13 base goodwill boost (greatly depends on social stat) if you have at least -70 rep.

Secondly, there is the ability to take one of their fallen faction members and take them in as a guest and heal them. Returning a faction member in “good health” to the edge of the map and effectively to the faction members will improve the goodwill by +15. This means the member must be fully patched up at that time, but it does not matter if he has not fully healed, has permanent health damage such as scars or removed organs, or is sick from disease. Pirates will not be affected, and will always stay hostile to the player.