The theory is that the Golden Throne was created by the Necrontyr as a weapon against the Old Ones. The Necrontyr didn't have real psykers so they designed the Throne as a psychic enhancer/resonator to level the psychic playing field between them and the Old Ones. They quickly discovered that they didn't have enough latent ability or psyker "fuel" to make it work and abandoned it.
Fast forward to Big E and Malcador finding the Throne and realizing it's true abilities. Big E uses it as a resonator in the webway project but finds out that it can also be used as an enhancer if Psykers are used to fuel it. The increases are small and as the person seated on the throne is enhanced, it requ