The Seiren Island is named after creatures called the Seiren of the Greshun mythology whom said attracts any sailor with their enchanted singing. Sailors generally avoid the island's waters due to the rumors of being cursed while no ship have seen to survive entering its archipelago.
Seiren Island has its own and unique ecosystem although its climate may be considered tropical despite it's a part of the Eresia Continent. Its southern parts consists of shore lines, high cliffs, deep forest, and a forest that looks like coral reef system. The northern parts have low to high mountainous parts with the ruins of Aegian City just north of the Gendarme Mountain, while the Great Tree of Origins is nestled between the city and the mountain range.
The island is also the home of Primordials, or Ancient Species that looks exactly like dinosaurs.
Long before the time of humans, the island had its own civilization. The Eternians, whom were the last race to have lived on the island were not the first to have made it their home. Their existence, and all before them, were wiped out that's caused by the will of the Great Tree of Origins called the Lacrimosa,