Returning to the empire, the elder brother at once started work on his slave races and soon perfected the process. Quickly creating different races for different tasks the slaves enable the empire to spread rapidly. It success built on the toil of undying, unquestioning slaves.
The Fay word for the slaves has survived through the millennium - golem.
The slaves were created in vast breading farms. Factories that produced creatures of living flesh that lacked a soul or any sort of self-awareness. When first created they were living, breathing and mortal creatures but that was not good enough for the Fay.
Each slave had a magical gem, the size of a fist, embedded into its chest. The magic in it removed the need for food, to eat or for air to breath. It prevented aging and kept the slaves at the peak of the physical condition. Most importantly, it made the slaves completely obedient to the Fay's orders. Not only was resistance or disobedience impossible, the mere thought of it was impossible.
Once a slave was set on a task, it would work on it continually. Never tiring, never questioning. Only stopping when the task was complete. Their muscles literally built an empire.