Follower = mercenary, companion, slave, brahmin or dog
Ability to lead over world map is based on players Charisma and perk Magentic Personality.
You can lead on WM 1 character (including yourself) for each point of Charisma. Perk Magnetic personality adds 1 Charisma (not capped) for purpose of leading over WM.
>>Maximum number of followers on wm is 10, 11 characters including yourself.
Number of mercenaries player can hold is based on partypoints(~pp). Factors influencing partypoints are (Charisma +10pp per point, Speech +1pp per 3%, perk Magentic Personality +50pp, trait Good natured +50pp)
>>Maximum number of partypoints is 300, "cheapest" mercnary costs 35pp. Maximum mercenaries is 8
Number of slaves player can hold is based on number of companions+mercenaries, basic amount of slaves, perk Good natured and perk Loner. Basic amount of slaves each player can hold is 2. Add 1 slave for each companion or mercenary tied to character. Perk Good Natured prevent you to hold any slaves. Perk Loner prevent you to hold any follower.
>>Maximum number of slaves player can hold is 9 (2 = basic amount, 7 = each for "cheapest" mercs, where you can hold maximum 7 of them with maximum partypoints excluding perk Good Natured)