How to Install Mutators for Killing Floor

A mutator is a game modification that only partially changes the game. Unlike mods, which generally cannot be combined (no more than one mod can be active in a game at the same time), multiple mutators can be enabled simultaneously in one game.

Mutator Types

Most often, KF mutators come in four types:

1. Regular mutator, modifying some game rules (armor welding, new ScoreBoard)
2. Weapon mutator, adding new weapons to the game (Hunting Rifle, PortalTurret)
3. Monster mutator, adding a new enemy to the game (Brute, HellFire)
4. Skin mutator, adds a new player model to the game (Stig)

There are also entire mutator sets, such as WTF or Hiyokomod, combining all three types described above. Installing such sets is similar to sequentially installing each type separately.

Installing Regular Mutators

Let’s consider the process of installing the first type of mutators using the example of the well-known ServerPerks mutator version 5.10.

In the downloaded archive you will find five files: ServerPerksV5.ini, ServerPerksV5.u, ServerPerksV5P.u, ServerPerksMut.u and ServerPerksMut.ucl. All mutator files with such extensions must be added to the System subfolder of the main Killing Floor game folder.

The key to connecting almost all mutators lies in their .ucl files. Open ServerPerksMut.ucl with a regular notepad and you will see the following text:

Mutator=(ClassName=ServerPerksMut.ServerPerksMut,GroupName=KF-Stats,IconMaterialName=MutatorArt.nosym,FriendlyName=ServerPerksMut.ServerPerksMut.FriendlyName,Description=ServerPerksMut.ServerPerksMut.Description,FriendlyName=ServerPerksMut.ServerPerksMut.FriendlyName,FallbackName="Server Veterancy Handler V5",FallbackDesc="Use perks as privately on this server config instead of getting from global steam stats.")

We are interested in 2 fragments:

• FallbackName="Server Veterancy Handler V5"
• ClassName=ServerPerksMut.ServerPerksMut

By the name Server Veterancy Handler V5, the mutator can be found and connected when creating a waiting server on the Modifications tab, by double-clicking on its name with the left mouse button. This way you can add all necessary mutators before starting the server.

Using the code ServerPerksMut.ServerPerksMut, the mutator can be added to the dedicated server startup line. For example:

ucc server KF-WestLondon.rom?game=KFMod.KFGameType?Mutator=ServerPerksMut.ServerPerksMut?VACSecured=true?MaxPlayers=16?ini=killingfloor.ini

If you need to connect several mutators, list them separated by commas:

Mutator=ServerPerksMut.ServerPerksMut,WeldArmor.WeldArmorMut

Important: The order in which mutators are applied can be important. For example, if a mutator “disable welding” is applied after a mutator “weld armor”, the ability to weld anything disappears. If mutators are applied in reverse order, the ability to weld doors disappears.

Installing Weapon Mutators

Let’s consider the process of installing a weapon mutator using the example of Colt Python version 1.2.

In the downloaded archive there are several folders, the contents of which must be copied to subfolders with the same names in the main Killing Floor game folder. If in some mutator all files are collected in one place, follow these rules:

• Copy .ukx files to the Animations folder
• .uax to Sounds
• .usx to StaticMeshes
• .utx to Textures

About .u, .ucl and .ini files is written in the previous section.

Open the WhiskyColt.ucl file in notepad:

Weapon=(ClassName=WhiskyColt.WColt,PickupClassName=WhiskyColt.WColtPickup, AttachmentClassName=WhiskyColt.WColtAttachment,FriendlyName= WhiskyColt.WColt.ItemName,Description=WhiskyColt.WColt.Description, FallbackName="Colt Python",FallbackDesc="A Colt Python .375")

Find the fragment:

PickupClassName=WhiskyColt.WColtPickup

Using the code WhiskyColt.WColtPickup, you can add weapons to the Killing Floor shop as follows.

You should install ServerPerks mutator version 4.36 or newer or Custom Shop version 2.

If you use ServerPerks, open the ServerPerksV4.ini file and add at the end:

TraderInventory=1: WhiskyColt.WColtPickup

If you use Custom Shop, open the KFCustomShopMutV2.ini file and add at the end of the file:

WeaponForSale= WhiskyColt.WColtPickup

After this, the weapon will appear in the Killing Floor shop.

Installing Monster Mutators

The code for adding a monster cannot be obtained as simply as in previous mutator types. Most often it is provided together with the mutator or on thematic resources.

After you have the desired code, you can proceed. Let’s consider adding the Shiver monster to the game. The code for adding it to the game is Shiver.ZombieShiver.

Let’s make it appear together with regular Clots. Open the killingfloor.ini file, find the [KFmod.KFGameType] section and lines like:

MonsterClasses=(MClassName="KFChar.ZombieClot",Mid="A")
MonsterClasses=(MClassName="KFChar.ZombieCrawler",Mid="B")

And add your own:

MonsterClasses=(MClassName="Shiver.ZombieShiver",Mid="Z")

Pay attention to the fragment Mid="Z". In quotes, you should specify a letter that is not used in existing lines (A, B).

Next, in the same place, find lines like:

MonsterSquad=3A1B
MonsterSquad=2A

And add 1Z at the end:

MonsterSquad=3A1B1Z
MonsterSquad=2A1Z

Enable sandbox on the server and now Shivers will appear together with Clots (letter A) and Crawlers (letter B).

Installing Skin Mutators

In ServerPerks since version 5, the ability to connect additional skins for players appeared. Let’s consider adding a new skin using the example of the Stig model.

Download the archive with the model and unpack the files according to the rules described above. Pay attention to the file ending with Mod. For Stig it’s KFStigMod.u. The code for adding a character will be the letters located to the left of the ending mod. In this case, it’s KFStig.

Open ServerPerksV5.ini in notepad and add at the end of the file the line:

CustomCharacters=skin_name

For example, for Stig it’s:

CustomCharacters=KFStig

Now you will be able to select the Stig skin in the regular skin selection menu.