tugrulas: At the game folder "Majesty 2 Collection\resource" there is a file called "resource.pak".
Open it with a archiver such as 7zip.
Under gamedata/units unzip the file "prg_params.xml" to the folder resource.mod\gameData\units.
You can edit the file to change bunch of things.
I usually increase peasant and taxer HP, which is enough to pass hard levels.
I trried editing but I get the message that the files are damaged and I must reinstall the game