The Empty Throne was both the time period of the Venerable Empire of Whide Axis between the end of the First War of the Power -with the disappearance of Emperor of the Elves Altarin and The Cataclysm of 2675 a.a.H, and a way to refer to the government of the Venerable Empire of Whide Axis after the disappearance of Altarin.
Altarin, Emperor of the Elves, an ambitious ruler that wanted to reinstate the imperial authority within the Whide Axis, took part in the First War of the Power in part to push further his imperial agenda, which worried the ushaverican local elites that resisted a reinstituted empire.
When Altarin disappeared during one of the final battles of the First War of the Power, the electors of the emperor -controlled by the Purple Party, a political opposition to imperial authority-, saw this as an opportunity, rather than to elect a new emperor mantained that, as it wasn't confirmed the death of Altarin, he was still the Emperor of the Elves until his return, or when his death was confirmed:
this resulted in the Empty Throne, of an empire without an emperor.
Because of this legal fiction kept by the Imperial Electors, Altarin technically was the longest serving Emperor of the Elves for 850 years, between 2147 to the 2997 -the final abolition of the Empire-.
For this long absence, many legends, stories and narratives will be spun around the vanished emperor of the Elves. As well, in several times of crisis, there would be some movements to claim a new emperor, but none of the fake emperors was widely recognized within the former empire.