”THEY CALL FOR A STORM. MY OPPOSITE. DEADLY
The Everstorm is a powerful weather pattern on Roshar similar to a highstorm. The Everstorm was summoned by Stormform Listeners during the Battle of Narak at the end of the War of Reckoning. It appears to be referenced as being the same thing as the True Desolation by Honor in Dalinar's visions, but it is possible the Everstorm is only a part of the True Desolation. According to Sylphrena it has not been summoned in previous Desolations.
Where regular highstorms are products of the Stormfather, a splinter of Honor, the Everstorm is not of Honor. It is of Odium. The storm travels from west to east, opposite the direction of traditional highstorms. It attracts stormspren and has the unique physical feature of red lightning. It also has the side effect of transforming any Parshman who come in contact with it into a Voidbringer. This has obvious and terrible consequences for the other inhabitants of Roshar. Because of the Everstorm's backwards path and unexpected summoning, Rosharans will be nearly defenseless against its destruction, as both stormwardens and physical barriers will be useless against it. It is noted that it will round Roshar less frequently than a highstorm.
”Brightlord, I have never heard it before, but the rhythm is one of destruction. Of power.
As Alethi forces approached Narak the Listeners awaited them and began singing a new song. Rlain warned Dalinar that the song should not be allowed to be finished under any circumstances. Dalinar subsequently ordered Adolin to stop the song at all costs. A daring attack was launched by Adolin on a group of reserve Listeners, who were leading the song. During the battle, Adolin defeated the Parshendi Shard bearer Eshonai, but they were too late.
The Everstorm crashed into a regular highstorm, which was produced by the Stormfather. The resulting tempest was capable of breaking and throwing entire plateaus from the Shattered Plains into the sky. 
In Yeddaw Lift heard reports that the Everstorm had started to strike countries in the west of Roshar. It was reported to be moving slower then a regular Highstorm. She was present as the storm struck Yeddaw. There was no stormwall as in a regular Highstorm. Nale saw the storm and parshmen wearing Stormform and was convinced that he failed in preventing the return of the desolations.
The Fused are ancestors of the singers. They are bonded with a modern singer, which this kills the singer they bonded with, and have access to powers similar to surgebinding. If a Fused is killed they are reborn during the Everstorm, assuming they can find a parshman body willing to latch onto, or at least one that cannot refuse entry of a Fused.
In Oathbringer, Everstorms settled into a somewhat regular pattern of occurrence, like Highstorms, with one coming every nine days. However, the frequency and level of destruction brought by Everstorms varies depending on what best serves Odium.
|War of Reckoning|
|Battle of Narak||Everstorm||Unknown|