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

Added 4 minutes ago
Too bad. I just remember that there's a connection with the skeleton/animation. If you've tried applying the Titan's animations to another creature, you might remember how it swells to enormous sizes. And those that are more or less compatible (Earth Elementals) can pass for their giant version with such an animation. 🤔

Read this thread from page 280, where there are posts about the Yeti... unfortunately, I forgot whether I only increased the model or only the animations, or both together, but this was done in a 3D program, and then the scaled-up/scaled-down model was exported into the game...
P.S. The skeleton is made for the model and is directly attached to the model, even if the names of the bones match for different models, their basic poses (in silhouette) may not match, which means that the bones will move the model differently....