Invincible units
Note: This cheat involves editing a game file so make a backup copy of the file before going on. Then use an archival utility like WinRAR to extract the files that are in the "game.pak" file in the "\ubisoft\faces of war\resource" directory. Especially extract the "tactis.dl", "normal.dl", "hard.dl", and "easy.dl" files in the "set/difficulty" folder in the "game.pak" archive file. Then use a text editor to edit the extracted files and change value under the "ally" header in each of the files to this:

ally
health_increase 40
health 40

Now add the modified files back to their orior locations within the "game.pak" file with WinRAR or another archival utility.