The Toran Lake Castle (トラン湖の城, Toran Ko no Shiro) is a location in Suikoden.
It is an abandoned castle in the middle of the Lake Toran, and it is covered with fog and monsters. Tir and the party managed to reach it with the help of Tai Ho who was the only fisherman in Kaku foolish enough to help them get there.
They managed to reach the center of the castle through the basement cavern, filled with monsters of all kind.
Once the Zombie Dragon was defeated, the fog was lifted and they could now use the castle as their new headquarters. The basement part was closed completely to the public and couldn't be accessed anymore.