The Island of Rosailic is where the name for the town of "New Rosailic" (Osion) comes from. It consists of a main island, 2 smaller islands with towers on them (Crying Tower, Other Tower), and a massive fortress city. The entire island is in disrpaire due to being abandoned by Mecharic, who crafted the fortress and everything else on the island. There is a single Iron Golem wandering it, which makes it somewhat safe from mobs.
History of Rosailic
(this is all role playing history, you can read it at the island too) Rosailic was a peaceful ocean empire with many allies and friends in the age before this one. However, as it's wealth grew, so did the jealousy of it's allies. Finally, one of them, the name is not remembered, betrayed Rosailic. They rose the undead, among other monsters, and attacked the peaceful people of Rosailic without mercy or hesitation. Rosailic lost all but it's capitol, the actual island of Rosailic, and it's Fortress, in the first great attack.
Having lost everything but their capitol, the people of Rosailic prepared for the fight of their lives. They summoned great iron golems from the deeps, snow golems were brought in with refugees from the colder regions, and many wolves and cats were raised to help fight the monsters from the unnamed enemy. The enemy brought their demons and undead, as well as siege weapons great and small. The battle for Rosailic Fortress would be brutal and bloody.
As the two great armies fought, it became immediately obvious that Rosailic would lose. They had not the resources needed to win the battle, and as such sent out a small fleet of civilians with a few soldiers to build a new Rosailic somewhere. The people left behind fought to the last man, woman, and child, but they lost. The Keep and Fortress, however, were rendered uninhabitable by the damage, and the last act of the Great Rosailic was to destroy the black magics that allowed their enemy to control the monsters and demons.
Rosailic Island now is just an abandoned wreck, but there are signs that both great peoples still fight. A boat, lacking sails or any means of power, docks at the island. A single Iron Golem, left from the war, wanders it aimlessly. The freed monsters still haunt the halls of great Fortress and Keep. And every so often, if you're lucky, you may see one of the old defenders, trapped by their unfinished business within the great structures of that island...