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

By the way, it could also be done this way! Because, in principle, these are: champions, masters, embodiments of dragon gods, etc., and they essentially have nowhere else to improve!

Then, it could be done like this:
Humans - Angel and Dragon
Elementals - Phoenix and Mystic Eagle
Necropolis - Fallen Angel and Bone Dragon
Naga - Naga General and Kirin
Magic Horde - Monsters and ?
Dark Elves - Golems and Giants
Lizards - Hydra and Great Basilisk
Mountain Orcs - Stone Giants and Cyclops
And with this, we will have the opportunity to create a third unit for each faction or seven neutral units.