Eiru
Although information remains fragmentary it appears that the world and its moon Bres were cast out of the Alusian plane during the war and lost to the Deep Void or Outer Dark.
The mechanism for this is not known but it appears to have also involved an effect similar to cases where individuals have been written out of fate; memory of Eiru was significantly reduced, with many sources failing to record its disappearance and others relegating the entire world to myth and legend.
There are no known portals or Elven Ways connecting to Eiru at the current time and the method used by the Celestial Pioneers group to reach Eiru involved unusual powers. The same group were extracted through the assistance of the ancient dragons Dumuzi and Nin-gizhida, who it is thought may be able to return there.
Bres
The only known moon of Eiru, believed to be host to a Calamar base, suffered a catastrophe some time after it was cast into the void, throwing it into something resembling a cometary orbit.
In recent years, Bres has been observed from Alusia as a comet. First sighted some 300 years ago, the small wandering body was named Lelyar, by Astromancers in Alfheim.
The comet, whose name translates as “the Traveller” appears once every 60 years or so, only becoming visible inside the orbit of Thunor, and disappearing again as it crosses that orbit on its journey outwards.
The Celestial Mechanics group encountered denizens of Bres who has crash-landed in Jotunheim.