Isla Sorum is a remote, artificial island of the west coast of Vanaheim. 
The Island is built of the dark-gray metallic substance, with six crimson circular markings at its outer edges.
The Great Race War
The Battle of Midgård
During the opening battle of the war, the contact was lost between the island and the feline capital of Midgård.
https://www.stormtale.net/en/aesir-chronicles-fates-vol-2-artika/ (Mentioned only)