Friendly Fire is a setting that features in all Call of Duty Multiplayers, and is most commonly associated with Hardcore game modes. In Core game modes, the setting is usually disabled, but a Private Match can adjust these settings. Friendly Fire enables all players to damage teammates. In player terms, this is sometimes referred to as team killing, and players that commonly do so may be referred to as team killers. In all Hardcore Multiplayer game modes, there are four separate ways to treat friendly fire: have it enabled so players can hit teammates, reflect/ricochet prevents players from damaging players, but will return damage dealt to friendly players to the shooter, have it disabled so it's impossible to shoot a player's teammate, and shared, which allows the player to kill friendly players, but the game will inflict damage to the shooter based on the damage dealt.
Killing teammates is often done accidentally, which in turn can lead to it being used as a form of revenge to reciprocate a team kill, or for any number of reasons including "griefing" (to deliberately harass other players). "Griefing" is more popular on Call of Duty 4: Modern Warfare and Call of Duty: Modern Warfare 2 as the teamkiller will only serve a time penalty and not be kicked from the game.
Servers on the original online multiplayer and its sequel could or couldn't have friendly fire turned on. At the time there were four options: "Disabled" in which the player could not kill teammates; "Enabled" which meant the player could kill teammates; "Reflect" which is popular since team-killers will actually kill themselves rather than teammates; and "Shared" which is a combination of Enabled and Reflect.
In Call of Duty 3, friendly-fire can now be responded to; if a person is team-killed they will now get the option to either punish or forgive the player. Punishing takes away 3 points from a player's score, often resulting in negative scores on the scoring boards, such as -15 for five team kills and no legitimate kills. If forgiven, the team-kill will have no effect, as it might have been by accident; however, it is up to the killed player to forgive or punish, so an accidental kill may result in a punishment anyway. Players are kicked after 9 team kills. Teamkillers may play as the medic class, teamkill and then revive the teamkilled player just so they can teamkill on the same player again.
In the case of trying to win the game, players will sometimes forgive team killers simply to retain their scores.
The Call of Duty 4: Modern Warfare manages team kills more simplistically. The only game modes where friendly fire is possible are "Hardcore Team Deathmatch", "Hardcore Headquarters" and "Hardcore Search and Destroy". In Hardcore Team Deathmatch, the player has no choice over whether or not they are punished or forgiven. Often, Team Killers will enter Hardcore Search and Destroy with RPG-7 x2, Sonic Boom, and Martyrdom, and at the start of a match, they take out the RPG-7 and blast the ground, killing everyone around them. Hardcore Search and Destroy is one of the most popular Team-killer modes in the game only for the reason it has Friendly Fire enabled and that the player doesn't respawn. Upon two team kills the player will automatically die and every other team kill thereafter. If a player teamkills at the beginning of a game/round they will die and serve a time penalty.
Many aspects of team-killing are the same. Hardcore mode is still the only one with friendly fire enabled. Team-killers will often enter Hardcore playlists armed with Bazookas, lots of Grenades, Satchel Charges, and any gun they carry and wreak havoc on teammates. Upon killing three teammates the player will be kicked unless they are the host; the host, however, is free to teamkill with no limits. If a player kills a teammate within a few seconds after a match starts, they will die as well and will lose 1 point for a suicide as well as the 10 points for team-killing.
Team killing is still possible in Call of Duty: Modern Warfare 2 in the Hardcore game modes. However, there is a Hardcore Ricochet: S&D that prevents players from killing their teammates by reflecting the bullets and killing the player. In private matches, players will never get penalized for friendly fire. They are free to constantly team-kill with no limits. The most common team killing in this game is for Care Package and/or Emergency Airdrop crates, as players will wait for the package to come down and kill the owner if there is a high killstreak inside, such as an AC-130 or EMP. However, the new game mode, Hardcore Mosh Pit has multiple games without "Shared" on, so teamkillers are far more likely to join this instead of Hardcore Team Deathmatch. Team killers are likely to use launchers such as the RPG-7, the equipment C4 and Danger Close (perk).
Killing a teammate right at the start of a game will result in the player instantly dying as well.
Call of Duty: Black Ops team killing remains same as Call of Duty: World at War, with team killers being kicked from the game. As in Call of Duty: World at War, the player will be kicked automatically after three team kills unless they are the host, where the player will not be kicked but will die and have a time penalty like Call of Duty 4: Modern Warfare. Also in the feed it will say "cannot kick the host player". In both cases, both factions will make a remark to exclaim that the player has been kicked.
When Call of Duty: Modern Warfare 3 was released team killing was allowed in all Hardcore game modes, however due to players abusing the ability (especially in Search & Destroy) this was soon patched, causing damage to reflect onto the shooter (Ricochet). The game modes where also retitled to match (Hardcore Team Deathmatch became Hardcore Ricochet: TDM). The most common form of teamkilling is jumping in front of a firing teammate, whether it be a launcher or through bullets, resulting in the death of the shooter. The other most common form of teamkilling is when the player sets down any killstreaks or equipment a teammate can destroy it. As of October 5th, 2012, players can now teamkill again on the Hardcore Face Off 3v3 mode and Hardcore Mosh Pit.
Team Killing makes its first appearance on the DS, and is a host-controlled function in Public Matches and Private Matches, unlike in console titles. The host has the option to have Friendly Fire turned on or off in both Public and Private Team-Based Matches. However, even if the host has Friendly Fire turned off, the player can still knife and throw knives at other teammates, possibly a glitch that wasn't meant to happen. Nevertheless, players cannot aim directly at a teammate when they use or throw their knife, but aim away from the teammate. If using a regular knife, when friendly fire is off, one must aim to the sides of the player, press the Fire button, then when the knifing animation is starting, aim at the teammate. When throwing knives at teammates when friendly fire is off, the player must again aim away from the teammate, like when knifing, and when the player just begins to raise the knife back to throw, aim at the teammate. Unlike its console counterpart, Defiance has no Ricochet, which they player may use to their advantage.
Call of Duty: Black Ops II featured a number of Hardcore game modes, and in private matches there is a server option for teamkilling, with the following choices:
- On - Where Friendly Fire is enabled.
- Off - Where Friendly Fire is disabled.
- Reflect - Where if a player kills his teammate, the game will kill him as well and will count as suicide.
- Shared - Where if a player shots his teammate, their health percentages will be the same even if the shooter wasn't shot.
The default teamkill limit is three teamkills before being kicked; however, all of those settings can be adjusted in Private Match settings. When the player is the host, they will not be kicked, but simply serve a respawn delay penalty. In the case of a player being kicked or the host serving a respawn delay, the multiplayer announcer for both teams will make a remark noting this. In Hardcore, formerly the option for Friendly Fire was set to Reflect, but in an update, it switches to On.
Call of Duty: Ghosts does not allow teamkilling in public matches, as the mode is selected to ricochet, so a teamkiller will actually kill themselves instead of a friendly. In Private Match, the host can select different modes such as regular friendly fire, ricochet or shared as well as not having friendly fire altogether. If friendly fire is on, a teamkiller can kill without consequences. In ricochet game modes, the player may still grief other players by running in front of players whilst they shoot, dealing damage to them via ricochet damage, and possibly killing them.
Call of Duty: Advanced Warfare has Friendly Fire enabled for all Hardcore game modes. When the player reaches at least three teamkills, they will be kicked by the server. If the server is a peer-to-peer based server instead of a dedicated server, the host of that server may not be kicked. Again, settings for how Friendly Fire is dealt with, and the teamkill limit, can be subject to change in a Private Match.
- Before a patch, there wasn't a teamkill limit in effect for Hardcore Search and Destroy in Call of Duty: Advanced Warfare, so players could have simply killed the majority of their team using a MAHEM as soon as the round started, and wouldn't be punished.