Elias Endures

This myth is a persistent one throughout the world, despite the best efforts of the empire to squash it as such. The conspiracy theory comes in a few varieties but in short they all describe the same phenomenon, that by some means the original emperor Elias Wistendayl lives on in secret hidden away somewhere. A truly ludicrous notion as even with the powerful magics of this world immortality is as of yet unachievable, though that hasn't stopped the speculation.
A persistent myth, carried both in and outside the empire, is one speculated on in fear by most but in hope by the most blindly loyal of the empire. With no recognized heir to take the throne there is this twisted hope that somehow the wisdom of the Wistendayl family is still at the helm of the empire.

Summary

"Elias is alive" in one form or another is the short version... the method of his endurance varies from version to version but they all agree he is still even after all these years quietly pulling the strings on his namesake empire from the shadows.

Historical Basis

During the time of Elias' rule there were a wide range of rumors about the Emperor mainly pertaining to why he felt the need to forge the empire, and to a rumored lust for power. After his passing during the rule of his brother, people often invoked the memory of Elias "Is this what he would've wanted?" questioning the judgment of those in charge. This reverence for Elias' beliefs about how the empire should function, combined with how Elias often spoke of an enduring empire were amalgamated with the rumors about a desire for power mutating into rumors the emperor sought not just for the lasting empire but for his enduring reign over it.
Over time the rumors turned myth, lost and refound over the decades, would warp and distort into a variety of far-fetched schemes of immortality.

Spread

The specifics of the myth aren't widely known, the existence of a myth most definitely is though.

Variations & Mutation

The main variation for the myth is the method. Some people say he wished himself immortal, others claim a pact with demonic forces, some suspect he fell into the dark arts of lichdom, while others believe his brother simply had his head preserved so they could cast a form of speak with the dead upon it when the need for his advice arose. Whether by benevolent or malevolent means and purpose they all believe he's still steering empire through the seas of fate.

Cultural Reception

It's completely dismissed out of hand by the vast majority of the population, and those who do claim the myth carries validity are jeered and outcast by society.

In Art

There are some art pieces depicting Elias as a sort of puppet-master like figure, controlling the council of stewards and the empire in turn that are considered nods to the myths but these pieces are fringe art, not to be found in respectable museums or the private collections of citizens in good standing.