Non-Playable Character

A non-playable character (NPC) is a character whose actions are controlled by artificial intelligence and cannot be controlled by the player. Some of these characters are often an important part of the storyline. NPCs always appear in campaign and cooperative gamemodes.
==Gameplay==
There are three types of NPCs: hostile, allied, and neutral. Hostile NPCs will attack the player on sight with whatever is available at their disposal, or deter the player in some way. Allied NPCs will actively fight the enemies of the player and generally help them. Neutral NPCs will not engage in any combat whatsoever. 
NPCs on either side have the ability to enter vehicles on the map. This can give either side huge advantages. NPCs can enter the turrets and side seats of larger vehicles, and drive certain vehicles. Which vehicles and the NPC's skill with them, is dependent on which game is played.
NPCs have unlimited ammo for their weapons. However, they must reload once they are done their magazines.
===Generic NPCs===
Generic NPCs appear in every Halo game to date. Most of them do not provide much crucial development to the game's storyline. 
In Halo 2, Halo 3, Halo 3: ODST, Halo: Reach, and Halo 4 the player can switch weapons with allied NPCs, helping to resolve issues of low ammo or help optimize combat efficiency for your team of NPC. Conversely, you can obtain slightly more powerful weapons that may not be available on the ground.
Halo: Reach features the Fireteam system, which is a unique way of recruiting friendly AIs. 
Every Halo game allows the player to be stealthy and eliminate enemies from behind without alerting other NPCs. This mechanic is extended to have special animations in Halo: Reach, Halo 4, and Halo 5: Guardians called assassinations.
Halo 3: ODST and Halo: Reach featured a cooperative gamemode called Firefight, where players can fight waves of generic enemies.
In Halo 4 Spartan Ops, players can fight in various missions to complete objectives and kill generic NPCs. 
In Halo 5: Guardians gametype Warzone, players can fight a variety of different generic NPCs to earn points. 
===Unique NPCs===
NPCs feature unique triggers and dialogue that differentiate them from "normal" allies because they are vital to the development of the game's storyline.
In Halo: Combat Evolved, there are only four NPCs: Captain Jacob Keyes, Avery Johnson, Marcus P. Stacker and 343 Guilty Spark. Keyes is only seen a few times, but if he is killed, the mission restarts from the last checkpoint. 343 Guilty Spark is invincible and immune to any attacks on him during the game. Johnson and Stacker can be killed with no repercussions.
In Halo 2, all NPCs are invincible. They usually fight alongside the player and lead allies into battle. Most of the time they are also armed with stronger weapons and feature unique dialogue that is integral to the storyline.
In Halo 3, NPCs share the same characteristics of Halo 2s NPCs, but when they take too much damage, they will fall to the ground, lifeless, and stay there until the battle is over. Soon after, they will stand back up.
In Halo 3: ODST and Halo: Reach, the same rules still apply from Halo 2. However, certain NPCs are playable in some campaign levels (for example, Tayari Plaza is told from Buck's point of view, but he is an NPC ally in NMPD HQ). The only NPC excluded from invulnerability is Vergil.
In Halo 4, Thomas Lasky is the only unique NPC. He is completely invincible and doesn't flinch when shot. Halo 4 Spartan Ops also features Parg Vol as an enemy who can be fought.
In Halo 5: Guardians, both Blue Team and Fireteam Osiris are unique NPCs that are dubbed "Musketeers" by 343 Industries. The Musketeers can take damage and go into a "final stand" or "down-but-not-out" state from which they can be revived. Similarly, the Musketeers can revive players in the same state. Musketeers can also be ordered by the player to take vehicles, attack enemies, look at different objects in the environment, take weapons and move to different locations.Youtube: Halo 5 ViDoc: A Hero Reborn The Warzone multiplayer gamemode in Halo 5 also features "Legendary" enemies that are specific to the maps they are fought on.
==List of Generic NPCs==
<tabber>
Halo: Combat Evolved=
Faction 	Relationship to Player
UNSC Marines	Allied
Elites 	Hostile
Grunts 	Hostile
Jackals 	Hostile
Hunters 	Hostile
Sentinels 	Allied
Flood 	Hostile
|-|
Halo 2=
Faction 	Relationship to Player
UNSC Marines	Allied
UNSC ODSTs 	Allied
Elites 	Allied Hostile
Grunts 	Allied Hostile
Jackals 	Allied Hostile
Hunters 	Allied Hostile
Drones 	Allied Hostile
Brutes 	Allied Hostile
Sentinels 	Hostile
Enforcers 	Hostile
Constructors	Neutral
Flood 	Hostile
|-|
Halo 3=
Faction 	Relationship to Player
UNSC Marines 	Allied
Elites 	Allied
Brutes 	Hostile
Drones 	Hostile
Grunts 	Hostile
Jackals 	Hostile
Hunters 	Hostile
Sentinels 	Allied (Until Halo, then hostile)
Constructorss 	Neutral
Flood 	Hostile (Allied for only The Covenant)
Voi factory workers	Allied
|-|
Halo: Reach=
Faction 	Relationship to Player
UNSC Army 	Allied
UNSC Marines	Allied
UNSC ODSTs 	Allied
Elites 	Hostile (Allied only if an Elite in Firefight)
Grunts 	Hostile (Allied only if an Elite in Firefight)
Jackals 	Hostile (Allied only if an Elite in Firefight)
Brutes 	Hostile (Allied only if an Elite in Firefight)
Drones 	Hostile
Engineers 	Hostile (Allied only if an Elite in Firefight)
Hunters 	Hostile (Allied only if an Elite in Firefight)
Moa 	Neutral
Civilian 	Neutral
Gúta 	Hostile
|-|
Halo 4=
Faction 	Relationship to Player
UNSC Marines 	Allied
UNSC Spartans 	Allied
Elites 	Hostile
Grunts 	Hostile
Jackals 	Hostile
Hunters 	Hostile
Promethean Crawler	Hostile
Promethean Watcher	Hostile
Promethean Knight 	Hostile
Sentinels 	Allied
|-|
Halo 5: Guardians=
Faction 	Relationship to Player
UNSC Marines 	Allied
Elites 	Hostile
Grunts 	Hostile
Jackals 	Hostile
Hunters 	Hostile
Promethean Crawler	Hostile
Promethean Soldier	Hostile
Promethean Watcher	Hostile
Promethean Knight 	Hostile
|-|
</tabber>
==List of Unique NPCs==
<tabber>
Halo: Combat Evolved=
Character 	Relationship to Player	Levels Encountered
Captain Jacob Keyes 	Allied 	
*The Pillar of Autumn
*The Truth and Reconciliation
343 Guilty Spark 	Neutral 	
*The Library
*The Maw
Staff Sergeant Avery J. Johnson	Allied 	
*Halo
*The Truth and Reconciliation
Lat 'Ravamee 	Hostile 	
*The Truth and Reconciliation
|-|
Halo 2=
Character 	Relationship to Player	Levels Encountered
Master Gunnery Sergeant 	Allied 	
*The Armory
Commander Miranda Keyes 	Allied 	
*Cairo Station
Sergeant Major Avery J. Johnson 	Allied 	
*Cairo Station
Spec Ops Commander Rtas 'Vadumee	Allied 	
*Sacred Icon
343 Guilty Spark 	Neutral 	
*The Oracle
Brute Chieftain Tartarus 	Hostile 	
*The Great Journey
Heretic Commander Sesa 'Refumee 	Hostile 	
*The Arbiter
*The Oracle
Prophet of Regret 	Hostile 	
*Regret
|-|
Halo 3=
Character 	Relationship to Player 	Levels Encountered
The Arbiter 	Allied 	All levels except Tsavo Highway
343 Guilty Spark 	Neutral (Until Halo, then hostile)	
*The Ark
*Halo
Sergeant Major Avery J. Johnson	Allied 	
*Sierra 117
*Crow's Nest
*Halo
Commander Miranda Keyes 	Allied 	
*Crow's Nest
Gunnery Sergeant Reynolds 	Allied 	
*Sierra 117
*Tsavo Highway
*The Storm
*Floodgate
|-|
Halo 3: ODST=
Character 	Relationship to Player 	Levels Encountered
Gunnery Sergeant Edward Buck	Allied 	
*NMPD HQ
*Data Hive
*Coastal Highway
Taylor H. "Dutch" Miles 	Allied 	
*Kizingo Boulevard
*NMPD HQ
*Kikowani Station
Michael "Mickey" Crespo 	Allied 	
*ONI Alpha Site
*NMPD HQ
*Kikowani Station
Kojo "Romeo" Agu 	Allied 	
*Kikowani Station
Captain Veronica Dare 	Allied 	
*Data Hive
*Coastal Highway
Unnamed NMPD Officer 	Allied (Upon discovering Dr. Endesha's body if the player has collected 29 audio logs, turns hostile)	
*Data Hive
Vergil 	Allied 	
*Coastal Highway
|-|
Halo: Reach=
Character 	Relationship to Player	Levels Encountered
Carter-A259 	Allied 	
*Winter Contingency
*ONI: Sword Base
*Long Night of Solace
*The Package
Catherine-B320 	Allied 	
*Winter Contingency
*ONI: Sword Base
*Tip of the Spear
*Long Night of Solace
Jun-A266 	Allied 	
*ONI: Sword Base
*Nightfall
*The Package
Emile-A239 	Allied 	
*Winter Contingency
*ONI: Sword Base
*The Package
*The Pillar of Autumn
Jorge-052 	Allied 	
*Winter Contingency
*ONI: Sword Base
*Tip of the Spear
*Long Night of Solace
Sergeant Major Duvall	Allied 	
*Exodus
Ardo 'Moretumee 	Hostile 	
*Long Night of Solace
|-|
Halo 4=
Character 	Relationship to Player	Levels Encountered
Thomas Lasky	Allied 	
*Reclaimer
Parg Vol 	
*Spartan Ops Episode 3 - Chapter 5: Hunting Trip	
|-|
Halo 5: Guardians=
Character 	Relationship to Player	Levels Encountered
Petty Officer Second Class Linda-058 	Allied 	Unknown
Petty Officer Second Class Kelly-087 	Allied 	Unknown
Lieutenant, Junior Grade Frederic-104	Allied 	Unknown
Spartan Olympia Vale 	Allied 	Unknown
Spartan Holly Tanaka 	Allied 	Unknown
Spartan Edward Buck 	Allied 	Unknown
|-|
</tabber>
==Sources==
Category:Terms and Phrases