During your travels through the Commonwealth, you may encounter individuals who will join you on your journey:
Perks can be obtained by reaching maximum affinity with each companion.
Perk: Trigger rush - AP regenerates 25% faster if HP is below 25%
Location: Combat zone
Recruitment: Visit the combat zone and kill all the raiders inside, then talk to Tommy (in the fight cage) and agree to take Cait's contract.
Personal quest: Benign intervention
Likes: Lockpicking, drug/ alcohol use (before completing personal quest), aggressive and mean dialogue choices, pick-pocketing, you running around naked (yes, really. Fast travel repeatedly in the buff and her affinity will skyrocket)
Perk: Robot sympathy - +10 Damage resistance against robots
Location: Sanctuary (Hills)
Recruitment: Talking to him after completing Minutemen quest 01 - When freedom calls.
Likes: Helpful/ nice dialogue choices, healing Dogmeat with stimpaks, crafting weapons and armour (best method to raise affinity)
Perk: Combat medic - Once a day regain 100HP if HP falls below 10%
Location: Vault 81
Recruitment: Completing the sidequest Vault 81 and then undertaking Hole in the wall, tell her that you are Vault-Tec security and authorize her to leave.
Personal quest: Emergent behaviour
Likes: Helpful/ giving dialogue choices, healing Dogmeat with stimpaks
Perk: Know your enemy - Deal 20% increased damage to ghouls, mutated humanoids and synth enemies
Location: Cambridge police station
Recruitment: Complete Brotherhood of Steel questline up until Brotherhood of Steel quest 06 - Tour of Duty
Personal quest: Blind betrayal
Likes: You putting on power armour, crafting weapons and armour (best method to raise affinity), completing (repeatable) Brotherhood sidequests.
Perk: Cloak & dagger - +20% increased sneak attack damage and stealth boys last 40% longer
Location: Railroad HQ/ Old North church
Recruitment: Complete the Railroad questline up until Railroad quest 02 - Tradecraft
Likes: Lockpicking (best method to raise affinity), hacking (best method to raise affinity), using stimpaks on Dogmeat, dialogue choices that support synths.
Location: Red rocket truck stop
Recruitment: Find and interact with him at the truck stop.
Perk: Isodoped - If you have 250+ radiation damage, the critical hit bar in VATS fills 25% faster
Recruitment: Talk to him after completing the sidequest he big dig
Likes: Using drugs, you running around naked (yes, really. Fast travel repeatedly in the buff and his affinity will skyrocket), constructing in settlements, dialogue that helps ghouls.
Perk: Killshot - +20% chance to hit when aiming for a headshot in VATS
Location: Diamond city markets/ Third rail
Recruitment: Pay him 250 caps (can be reduced by persuasion) to join you.
Personal Quest: Long road ahead
Likes: Dialogue choices that result in getting more money, lockpicking (easiest method to raise affinity), pickpocketing, sarcastic dialogue choices
Perk: Close to metal - +1 additional guess when hacking terminals (doesn't stack with Science bobblehead) and terminals take half the amount of time to reset if locked out.
Location: Vault 114 (initial meeting)/ Valentine's detective agency
Recruitment: Rescue him from Vault 114 during Story quest 04 - Unlikely Valentine and then agree to him accompanying you.
Personal quest: Long time coming
Likes: Hacking (easiest method to raise affinity), using stimpaks on Dogmeat, nice dialogue choices.
Perk: Gift of gab - Gain double XP for finding new locations and successful persuasions
Location: Diamond city markets/ Publik occurences
Recruitment: Talk to her after completing sidequest Story of the century or she will join later after Story quest 04 - Unlikely Valentine
Likes: Lockpicking (easiest method to raise affinity), helpful dialogue choices, dialogue choices that avoid fighting
Perk: United we stand - +20 damage resistance and +20% damage when surrounded by 3+ enemies
Location: Museum of freedom
Recruitment: Talk to him in Sanctuary after completing Minutemen quest 01 - When freedom calls
Likes: Helpful dialogue options, completing Minutemen (repeatable) sidequests, customizing weapons (easiest method to raise affinity)
Perk: Berserk - Deal +20% melee damage if HP drops below 25%
Location: Trinity tower
Recruitment: Rescue him and Rex from the cell at the top of Trinity Tower during the sidequest Curtain Call and let him accompany you when you reach the ground floor.
Likes: Killing enemies (easiest method to raise affinity), eating corpses (cannibal perk), killing settlers
Perk: Shield harmonics - +20 energy resistance
Location: The Institute
Recruitment: Joins automatically after completing the Institute quest 03 - Mankind Redefined
Likes: You putting on power armour, hacking terminals, customizing weapons and armour (easiest method to raise affinity).