Fallout 3 companions

Permanent companions
There are 8 permanent companions (also known as "followers") available to the player in Fallout 3. Most have a Karma requirement that must be met if the player wishes to enlist that companion (listed here in parentheses).

Pictured, left to right:
 * Star Paladin Cross: Brotherhood Paladin (Good)
 * Butch DeLoria: Tunnel Snake (Neutral)
 * Clover: Paradise Falls Slave (Evil)
 * Sergeant RL-3: Mister Gutsy Robot (Neutral)
 * Jericho: Retired Raider (Evil)
 * Fawkes: Super Mutant (Good)
 * Dogmeat/Dogmeat's Pup: Dog (No Karma Requirement)
 * Charon: Ghoul Bodyguard (No Karma Requirement)

Though there are exceptions, the player is generally limited to enlisting Dogmeat plus any ONE other companion, barring certain system exploits.

Experience
Unlike previous Fallout games, the companions don't gain experience independently but are scaled to the level of the player; the player receives a debatable amount of experience while dealing damage alongside a party member. In the Xbox 360 version the player earns full xp if able to do the majority of the damage that kills an opponent (you get zero xp for a kill unless you manage to do at least 30% of the damage).

Combat
Companions come with their default weapons and armor and will use these, depending on what role you ask them to play (melee or ranged). They will also wear any weapons or armor they are given that is superior to their standard armor. All human or ghoul NPCs are capable of wearing Power Armor (this includes temporary companions such as Sticky, but excluding Fawkes as he is a Super mutant). Armor and weapons worn by companions never degrade with use.

Companions have unlimited ammo for their standard weapon (With the exception of Butch), but you'll have to supply them with the appropriate ammo for any other non-default ranged weapon.

If a companion is given several weapons and the appropriate ammo, they will generally choose a weapon based on the range of the projectile, then on either damage per round (DPR) or damage per second (DPS) but not by the in-game interface's DMG stat. For example, if you equip Star Paladin Cross with a Flamer, she will first attack with her default Laser Pistol because her target is out of the Flamer's range. She will move towards the target to get into the Flamer's range and then switch to it. There are exceptions, however. For example, Charon will always use Protectron's Gaze (a unique laser pistol) over the Laser Rifle, despite its reduced range AND damage per round rating.

Some companions (except Dogmeat) will use any weapon if you give it to them (provided they have appropriate ammo for it). There are some exceptions however, for example companions cannot use the Gauss Rifle rewarded upon completion of the Operation: Anchorage DLC, but can utilize the sim-only version obtainable through glitching or console.

You can have companions become pack mules for your rarely used weapons (such as the heavy Fat Man) for you without fear of them using them by simply not giving them ammo for the weapons you don't want them to use. Note however that it is possible the companion will find and pick up ammo for the weapon in containers/ground/bodies thus allowing them to use the weapon.

Companions have significantly more health than "normal" NPCs. Even wearing their standard armor (like Clover's pink dress or Butch's leather jacket), they can survive several high-power rifle headshots before dying. Give them Power Armor, and they can withstand a LOT of punishment in combat.

Companions are restored to full health at the end of combat, after all nearby enemies are dead. However, if you zone out during a fight and they follow while injured, or if they are injured outside of combat (e.g. a booby-trap), they do not heal (until after the next combat). They can also use stimpaks in their inventory in the middle of battle, if you gave some to them earlier. Dogmeat can't carry stimpaks, but you can speak to him in the middle of combat to heal him manually. Note that Dogmeat may be injured when you first acquire him (the injury is carried over from before you enlist him). You can check companions' health by viewing them in VATS mode, or moving far enough from them to see their HP bar. Companions are not considered 'vital' NPC's, so they will die if their health is fully depleted and there is no way of reviving them (unless you load a saved game).

Some Companions will enter sneak mode when you enter sneak mode, and end it when you do. They may also randomly enter sneak mode during combat, presumably to avoid enemy fire or to gain better aiming.

Your playing style is important when selecting a companion. Players who focus on stealth should consider Charon to be most useful due to his high (tagged) Sneak stat, and avoid companions like Fawkes and Sergeant RL-3 due to the fact that these NPC's can't sneak. Characters focusing on combat should consider taking stronger companions with more health, like Fawkes and Star Paladin Cross.

You can always hire more than one companion with the use of certain glitches; see Multiple Companion information on the discussion page of this wiki.

Statistics

 * For a detailed list of the companions' equipment, see Fallout 3 companion equipment.
 * Carrying capacity will be, e.g., 50 pounds less if given Power Armor (45 for armor, 5 for helmet). Capacity is determined by: (Base of 150) + (10 * Strength) - (Weight of inherent gear) - (Weight of anything else, including replacement armor or weapons)

Firing permanent companions
In most cases, companions can be dismissed/fired, and can later be found and rehired. In most cases, when fired they always travel to a specific spot, usually not the same spot they were hired. In some cases, they can always be rehired by simply finding them and asking them to rejoin you. In some cases, there will be Karma or other requirements. For example:


 * Fawkes: If fired, Fawkes will travel to the American History Museum where he will wait for you just inside the front door. You can rehire him any time so long as your Karma is good. No charge or other requirements to rehire him.
 * Sgt. RL-3: If fired, will travel to the entrance to Canterbury Commons (at the traveling merchants' stop near the trees), where he can be rehired so long as your Karma is neutral. No charge to rehire him.
 * Star Paladin Cross: If fired, returns to The Citadel. Can be rehired any time, but only if Karma is Good.
 * Butch: If fired, returns to the Muddy Rudder in Rivet City. Can be rehired any time, but only if Karma is neutral.
 * Dogmeat: Isn't really "fired," waits by Vault 101 as ordered.
 * Jericho: If fired, returns to Megaton, he is found inside Moriarty's Saloon, unless you blew up Megaton, then he just waits at the ruins. You must have evil Karma to re-hire him.
 * Charon: If fired, he will return to the Ninth Circle Bar. He can be re-hired anytime.
 * Clover: If fired, she will return to Eulogy's Pad in Paradise Falls (even if the player has killed Eulogy and abolished slavery by wiping out everyone in Paradise Falls).

Temporary companions
Temporary companions are companions that will join you during a quest. Most of them will follow you indefinitely until you complete their related quest, but not all. Unlike permanent companions, they do not heal automatically at the end of a battle.
 * Bumble - Actually a useless companion, since she cannot carry equipment and flees during combat (Note, however, that she can't be killed and can be used as a distraction).
 * Cherry
 * Initiate Pek (Falls Church Only).
 * James (Not actually a companion, as his AI has a set path to Rivet City).
 * Paladin Hoss (Falls Church Only).
 * Red
 * Sarah Lyons (Only During Take it Back).
 * Shorty
 * Sticky
 * Sydney
 * Unnamed BoS Paladin (Falls Church Only).

Operation: Anchorage only:

 * Sgt. Montgomery (Operation: Anchorage simulation only).
 * Strike Team Grenadier (Operation: Anchorage simulation only).
 * Strike Team Infantryman (Operation: Anchorage simulation only).
 * Strike Team Missile Unit (Operation: Anchorage simulation only).
 * Strike Team Mister Gutsy (Operation: Anchorage simulation only).
 * Strike Team Sentry Bot (Operation: Anchorage simulation only).
 * Strike Team Sniper (Operation: Anchorage simulation only).

Mothership Zeta only:

 * Elliot Tercorien
 * Sergeant Daniels
 * Private Beckett
 * Paulson
 * Toshiro Kago
 * Somah
 * Support Drone
 * Guardian Drone

It is important to note that some of the temporary companions can be given weapons and armor. In addition, these same companions can be utilized as "pack mules," with a weight capacity in the vicinity of 250lbs. Unfortunately, temporary companions are just that: temporary. Should you ever complete the quest the companions is tagging along for, everything the companions has in his possession becomes his. An example would be if escorting Sticky across the waste (under the pretense of taking him to Big Town), and you accidentally enter Big Town, Sticky and everything he has on him become his, and you'll have to kill him, or pickpocket him, in order to retrieve your belongings.

Bugs

 * Weapons given to companions may sometimes "duplicate" in their inventory. Checking it will show two weapons and no ammo, both equipped. Taking the weapon away and then giving it to them will fix the bug.