Players start Kenshi with a set number of player characters to customize depending on their selected Game Start. Across the world of Kenshi, there are many characters who can become player characters after certain interactions. After recruiting any number of these characters, players can control each squad member as well as all of them at once.
The maximum number of characters you can control is 30. This can be increased with mods fairly easily. Once players have reached 30 characters total, dialogue options will no longer appear for recruitable characters. Instead, they may notice drifters hanging around and even protecting your town without a word.
Note that having more characters is more computationally demanding and can affect game performance.
Most Recruits join the Player Faction through dialogue options found in towns. Recruits for Hire can be found patrolling town or hanging out in a bar. These recruits have a set fee for joining and become Player Characters immediately after receiving that money. This fee is generally between 3,000 to 7,500 cats.
Characters for Hire can be randomized Generic Recruits or Unique Recruits. Most randomized recruits start with very low stats, rag clothing, a simple weapon, and hunger. Unique recruits often have a few elevated stats (10-15) depending on their specialty (i.e. Medic) but are still relatively weak.
Slavery is prevalent across the world of Kenshi. Some Slaves are happy to serve their masters, but most are very appreciative to be freed by the Player. After freeing Slaves and Prisoners, they will become allied to the Player. They will appear green on the Map and will follow around the character who freed them. If they are kept safe for a while, they can potentially become Player Characters. Otherwise, they will run off into the wilderness to join back up with their faction.
Slaves and Animal Player Characters can be purchased from their owners. After Slaves are purchased from their Slaver Boss, they will be Allies. If they are kept safe for a while, they can potentially become Player Characters. The Unique Recruit Ray is an exception to this. After purchasing Ray from his master, he is automatically a Player Character despite still wearing Hive Prisoner Shackles.
Animals purchased from Nomads or Holy Farms are automatically Animal Player Characters and do count towards your character limit. More information on purchasable animals can be found on Guide to Animals.