Animation

It turns out that the banshee's animation is located in the Characters/Creatures/Necropolis/AlternativeUpgrade folder. I tried to move the messenger's ability animation to the banshee in this folder, but it didn't work. Then I tried to do the same with the banshee's attack, and it still failed; I can't understand what the problem is.

For simplicity, do this through the Map Editor. There, you can also study the "File Location" by using a "reverse scheme," i.e., by going into the creature whose animation you are interested in.
Also, creating a separate folder where you can extract a copy of the archive (data file) and then use a search engine within that folder to freely search for what you need and find out where it is located may help with finding the right files.
*) If necessary, I can explain it step by step with screenshots.