Overview
Lake Eternity is a vast indigo lake inside the Plains of Eternity, near the route between Zarephon and Myriandel. Travelers use it as a landmark. They avoid crossing it lightly because immense essence-rich creatures move beneath its still surface.
Geography
Lake Eternity extends to the horizon and is bordered in places by crystalline shores, cliffs, blue grass, giant trees, and forests. Near Myriandel, the city rises above the lake in terraces, with streams and waterfalls descending toward the water.
A wide river leads into the lake during Isandriel's pursuit of Thamrielle, and a large river flowing out from Lake Eternity leads south toward Ereshval waters. Roads and shore routes near the lake lead deeper into the plains toward the River of Eternity, the mountains, and the source. The source itself lies in a separate deep lake inside Zarephon's mountain cave, where white essence feeds the River of Eternity.
History
During the Eternal War, Myrravel and Ulzathir forces plan to skirt the lake on their march toward the source. Viviana and Gren later break away near the lakeside, where the water offers a potential escape route toward Ereshval.
Thamrielle follows the lakeshore to reach the source, relying on the lake's dangers to discourage pursuit. Isandriel's fleet enters Lake Eternity after gliding out of a wide river, then halts when a powerful creature moves beneath the ships. The creature lets the ships continue across the lake.
Before Zarephon is destroyed, Alice and Eliona fly close to Lake Eternity because their skyship needs to stay near visible ground on the route to Myriandel. Raphael has warned Alice to avoid whatever lies hidden within the lake. After Zarephon is destroyed, the forest leading down to Lake Eternity is leveled.
The Celestial Games later include catching a fish from Lake Eternity among the proposed extreme challenges.