[Yatun Island]
The core of the Yatun Duchy's archipelago and also the most central island, where the capital of Adun is located.
It is originally an island about 30 kilometers in radius, but after being repaired by the siblings Yellow Spring and Asura, Yatun Island's area had been slightly expanded.
Although the expansion wasn't significant, the shape had been redistributed.
The eastern plains, the western forests, the northern hills and mountains, the central lakes, and the southern beaches.
Outsiders looking to enter Yatun Island must land from the south, as the other three sides are enveloped by a huge barrier created by Lilith using fairy magic to protect this kingdom.
In addition, inside Yatun Island lies the entryway to Avalon, also known as Lake Avalon.
The area of Yatun Island itself is actually average; as a nation, it's rather modest, but if you include the Avalon World, then the area becomes extremely vast.