Though just a tiny island, Dereth is a very important place to the history of Auberean. It is a nexus of great magical power, likely due to a high concentration of Menhir Rings and Ley Lines. In ancient times, Dereth (then Killiakta) was the only territory of the early Empyrean Culture of Falatacot. Later, when the Falatacot left this world, it was under control of the Kingdom of Dericost. The House Mhoire fled to here to escape the Filinuvekta. The resting place of His Eternal Splendor is located under Marae Lassel. When the Yalain came to power, Ireth Lassel was used as a research colony. During the first Shadow War, when Bael'Zharon and his army of Shadows nearly crushed the Yalain, Ireth Lassel was their last stronghold. When the Yalain were defeated again, this time by the Olthoi, Ireth Lassel once again was their last stronghold, and to this day remains the only portion of Auberean not completely overrun by Olthoi.