Throughout your play of Rimworld you will come across several different types of characters. Some of these characters will be friendly such as drifters who just wander through your colony and other hostile, such as the mechanoids, looking to destroy you.
As of Alpha 14 (July 15th, 2016), traders, visitors, raiders, kidnappers, animals, etc. will now escape if surrounded by walls with no way out.
As of Alpha 16 (December 20th, 2016), rescued people (especially space refugees etc.) should sometimes join the colony. If the environment isn't survivable (e.g. bad temperature, toxic fallout) they should always join the colony.
Wild animals spawn on the map according to the biome and from random events. Unlike animals on, say, Earth, animals on RimWorld are all potentially dangerous. With just a little luck, a rat or squirrel, and certainly something as vicious as a tortoise or a wild turkey, can often take down and even kill a casually armored colonist, or at best leave them wishing they had never met the horrible beast. At least until you have some first-hand experience with them, do not underestimate wild animals!
These wild animals, and their tamed counterparts, will wander and graze on vegetation, including player-grown plants, regardless of type. Growing food outdoors can sometimes attract animals to your base perimeter. Animals are an important source of food by the meat they provide once hunted and butchered.
Raiders will target tamed animals as often as colonists.
Animal trainers receive 90 XP per training or taming attempt. When tamed "cute" animals nuzzle a colonist, it counts as a social interaction and is logged in the social tab of both the colonist and animal.
Main Article: Colonists
Colonists are the main protagonists in RimWorld. They are living inhabitants of each RimWorld colony, and the primary goal of the game is for the player to properly manage them. Each colonist has specific skills, positive and negative traits, and a character backstory. In general, every human is a colonist, except for raiders/travelers/prisoners. The colonists come in various outfits based on their background, which can be seen by looking at the 'Character' tab in game.
When managing the colonists, the player must take note of as many of the colonists' attributes as possible. These include, but are not limited to, managing their needs at all times, utilizing their skills to help with their progress throughout the game, increasing their skills, having them research technologies and build anything that helps them the most, and defend themselves against raiders - which include increasing their defenses with each passing moment.
When possible, playing into the strengths of each colonist, as well as their likes, will increase the player's efficiency of advancing through the game.
Main Article: Prisoners
Prisoners are people, usually raiders, hostile tribals, or your own colonists undergoing a mental break, who have been taken captive (they are just prisoners, not colonists now). They are unable to leave their prison barracks and can only use facilities, such as a nutrient paste dispensers or shelves, on their own if they are placed inside the prison barracks.
Raiders are essentially the main antagonists of RimWorld. They are predatory enemies who attack in groups when the storyteller's threat cycle is active (or any time, for Randy Random). The group size and strength of a raiding party is determined by 'points', which will be explained in-depth further down this article.
Occasionally an event is triggered that spawns a group visitors from a friendly faction at the edge of the map that comes and mills about the colony. Sometimes one member of the group has items to trade, indicated by a question mark over the pawn. To initiate trade, select a colonist and right-click the trader.
A visiting group's arrival could prove advantageous if the colony is assaulted by a mutual enemy while they are present. See Events - Visitors.
When leaving, visitors will carry away wounded members of their faction.