Plutonium

RCyclone519 I'm having the same issue. I'd like to get wacky with stuff like GIGN fighting the Militia, but I guess that's not possible right now.

Have you ever wanted to change up the factions that are on maps? Well I've found a way to do it, but it's not 100% working. Maybe someone who's more experienced with MW3 modding can figure it out, but I'll give a short tutorial on how you can change factions on maps.

First you need to locate the .arena file of the map. I can only find this on custom maps. They are located in the iw5/mp folder, as you can see here. Use notepad or similar program to edit .arena files.

There are several factions in MW3. However, only a few seem to work, and I don't know why.
The factions are:

delta_multicam (Delta Force, Works)
sas_urban (SAS, works)
opforce_air (Spetsnaz Paratroopers, works)
opforce_snow (Spetsnaz Snow troopers, works)
opforce_henchmen (Inner Circle, works)
These are the working factions. Simply enter their name, not the things in ( ) into the allieschar or axischar section:

These are the additional factions I found from this searching github. The factions do not work, so it's possible that these are not the correct names of the factions. I should note that the above factions do have files in iw5/zone/team_(team name).ff while the factions below do not.
gign_paris (GIGN, does not work)
pmc_africa (Private Military Corporation, does not work)
opforce_urban (Spetsnaz Urban troopers, does not work)
opforce_woodland (Spetsnaz Woodland troopers, does not work)
opforce_africa (African Militia, does not work)

Once you have the working faction in .arena file, save it and load up Plutonium. Pick you map and start a match. Once it loads you should see the two selected factions:

Even if the two factions are on the same "side", they can still fight each other, which is pretty cool.

I do apologize for picking a map with no color, this was just done as a simple showcase. If anyone is more advanced with MW3 modding, it would be nice to see the additional factions like GIGN work using this edit, as well as the locations of the stock and DLC maps .arena locations.