Belinsk Castle is the center of government for the country of Morgal, housing the Morgal royal family. The castle itself is built atop an extensive set of ruins, which could be entered directly from the castle. For a long time, however, only a small portion of the ruins were explorable and the passageway itself was known only to a select few. The castle is heavily guarded by soldiers and seems to employ a number of staff to serve the royal family.
Following the Morgal Revolution, where the native beastmen overthrew their Sanan occupiers, a young girl, Hou Ju, was captured and imprisoned in the castle's dungeon. At a later point, the Champan pirate Eoleo was also captured. Both were scheduled to be executed by boiling at an upcoming Festival. In reality, the captures had been orchestrated by Volechek and the Tuaparang commanders, Blados and Chalis as part of a bigger plot.
At some later point, Matthew and his group come to Belinsk during their quest in an attempt to rescue both Hou Ju and Eoleo. As the castle is otherwise impenetrable, the group is forced to enter and traverse the Belinsk Ruins via a hidden entrance. During their exploration, the entryway to the castle is cut off, forcing the group deeper into the ruins. It is only after Ryu Kou is forced to activate the ruins' hidden Alchemy Dynamo, which reveals the Luna Tower, that the Adepts are able to exit. Astonishingly, the Adepts are then allowed to enter the castle and rescue both captives. As the group leaves the castle, the Grave Eclipse, an effect of the Tower's revival, begins, causing many monsters to appear and attack the city. While numerous casualties happen outside, those in the castle appear to be relatively safe.