Animation

I have a question. I did everything as instructed, and it worked for the Death Messenger, but not for the Banshee. Is there some other technology involved?

No, it's the same process; there's no difference.

Maybe you mixed up the folders? The Undead faction seems to have two folders for alternative upgrades; perhaps you confused the names, and the game can't find the file (this is just a theory; it often happens to me).