RTF is a global modification that replaces all towns in the game.

In this case, I can suggest you take a look at the Sanctuarium Mod, which replaces the elves in the Sanctuary.

That's what we were talking about.

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On this channel (at the bottom), there are some soundtracks from Battle of Heroes. I think some of them can be used in the game.

Added after 23 minutes
+ In the city of Vintrial, on level 4, there are birds, and on level 3, there are some spirits that look like water elementals; I think they need to be replaced with someone else...