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

I finally had time to finish the animation... it's great!

Awesome!

Added 7 minutes later

Then everything is fine. It's an interesting unit; its physique is more like a bear than a monkey.

Well, it's easily explained... it happened like this: one very curious monkey (of a breed very similar to the nihon-zaru, or Japanese macaque, which is an incredibly intelligent variety) was transported through a portal by Ashi and ended up on an island inhabited by polar bears. There were many lonely female polar bears there, and eventually, nature took its course, and he had to satisfy the lonely white bears... as a result, yetis appeared.