Poliarnorosme

Some say they've seen it roaming the northern coasts, calling to the sea with an otherworldly sound. There are spoken tales of it descending from the northern lights to wander the harsh landscape, as it would seem, without a clear purpose. Descriptions vary but most have one thing in common - a trail of bright fog and small lights that stay up in the air for a moment, only to then dissolve into nothingness. This also does fit the oldest written record of an encounter with this creature, which also appears to be the source of the whole myth. At least, we can consider that, as there is absolutely nothing in any art or cultural material of the region before this document that would show any similarity to the creature in question. But then again, maybe we haven't found anything. Then, again, maybe this is not true at all. Edgards der Alksniskalva, explorer of the north of the Central Continent

Summary

The general myth speaks of a mystical creature which lives in the northern lights, called the Poliarnorosme (creature of the north lights). When the lights illuminate the sky, the Poliarnorosme descends down to the overworld and wanders around the forests and icy coasts of the north-east of the Central Continent. There is no clear purpose in what it does, as it seems to only watch. Some say it is a divine "guardian of the North", that protects its beauty and fragile secrets. Others say it feeds on the plant life found in the forests and that it is no more than just a completely bizarre animal. Many claim to have seen it, though no solid evidence exists.

Historical Basis

The oldest written record of the existence of the creature originates from around the year 1800 from a local chronicle, where a description of a fisherman encountering the creature can be found. It is considered the source of the legend, as no previous evidence of this myth exists.

[...]it drifted, as if air was its water. Never have I seen such grace in a living being, it moved as a velvet veil on the wind. The light was filled with so many colours, the whole forest seemed to be illuminated just from this single creature. [...] part of the description given by someone who supposedly encountered the Poliarnorosme