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

in the sixth game, the Rukh were

The Spirit World is divided into elemental worlds, each of which is inhabited by special types of spirits and elementals, the most powerful of which are dragons. The Thunder Bird, known in the writings of the Seven Cities as the Rukh, is one of the greatest spirits of Air. Being bound to the material world, the Thunder Bird causes storms and hurricanes with each flap of its mighty wings. Most often, the bird is summoned by mages or priests of Ilat through a complex ritual, but sometimes a Rukh egg appears on its own in a place where lightning has struck the ground.
it was a superboss, but after defeating it, it turned out that the Rukh can be of any size and strength, even tiny little birds.