The castle of the Masked One was a large castle located in the area called Shadowgate. Made from dust, the castle was the home of Kirsten and her prisoners Bede and Mariette, and acted as hiding place of the Sister of the North. Its carved rock walls had gleams of emerald and embroidered rugs covered its floors. It was destroyed and reduced to a smooth rock after Honora killed Kirsten.
When approaching the area Shadowgate, the rocks began to shimmer and slowly transformed into the castle.