Grimgar Of Fantasy And Ash Vol. 12 (Light Novel)

Level 12: That was the Beginning of a Legend Surrounding a Certain Island and Dragon
In order to return to Alterna, Haruhiro and the others head for the sea through a mountainous valley full of enemies. After many hardships, they finally arrive at the beach, where they find a ship that has been run ashore. Just then, a mysterious pirate girl with a fake mustache named Momohina appears and offers to lead them to the Emerald Islands, where dragons have been living since ancient times. What awaits them there is a pirate haven in chaos and under siege by dragons! The adventure story born from the ashes takes to the sea to spin a new tale.
Notice: This book is written in Japanese.