Was bored and wrote a very simple program to allow you to make any allies of the races you wish.

It's located here: http://buddhabox.ath.cx/wbc3/

If you're not into installing exe's from unknown people, the page also has the hex listings for the settings.

And they're included below.

Each value is two bytes in length. (So Knight would be x28-x29.)
Each can be filled with x14 00 (20 00) (or higher?) which sets the alliance.
These are signed values.

x28(40) Knight
x2A(42) Dwarf
x2C(44) Undead
x2E(46) Barbarian
x30(48) Minotaur
x32(50) Orc
x34(52) High Elf
x36(54) Wood Elf
x38(56) Dark Elf
x3A(58) Fey
x3C(60) Dark Dwarf
x3F(62) Daemon
x40(64) Empire
x42(66) Sarathi
x44(68) Swarm
x46(70) Plague

If you later anger the race(s), you can of course run the program/change the value(s) again.

I'm likely late to the party on this info, but I couldn't find it anywhere else.

Thank you for doing this!

Hey awesome., I would want to test it but the link is down. Could you please reupload it.:)
Thanx

Here's a dump of the webpage info. I added some extra functionality since it's creation. Although it's been completely solid for me, always back up your files!

Dropbox direct link: https://www.dropbox.com/s/fm209t7j67cksnd/WBC3Allies.zip?dl=0

Changes

03/04/18: Added checks on currently loaded campaign file.

02/21/18: Added ability to choose diplomacy relation by clicking the race.
(Blue-Ally[32 00], Purple-Friendly[05 00], Black-Neutral[00 00], & Red-Enemy[CE FF])
Also added buttons to change all to a default relation.
(Races must still be check to actually be saved in that state)
Changed money (crowns) to 8000. (0x40 0x1F)

01/24/18: Added ability to set character money (crowns) to 5000.
(Two bytes filled starting at x48(72), 0x88 & 0x13)

01/23/18: Added Status Strip with currently loaded file info & program icon

Program Use

This program is very basic and only changes the races you check.
Because of this you can even check the races before opening a campaign file.

The program defaults to C:\Users\<user>\Documents\Warlords Battlecry III\Saved Games
If your files are elsewhere, you will need to manually navigate there.

When you are ready, save the file. The program allows you to save it as another name if desired.
Always make a backup! I am not responsible for any damage this program might do!

The program is written in C# on Visual Studio 2013, using .NET 4.5.
Just unzip it, and run it from anywhere you like. There is no installer.