Standing close to the edge of the cliff on the east side of the inner precinct, it was built in different periods. The oldest part consists of two platforms that supported two galleries with a flat roof reached by a central staircase.
Later the center of the building was filled in, the staircase was extended and the east wall built. This produced a new base where a temple was erected with two vaulted rooms, three entrances, and a lintel supported by two serpent-shaped columns with their heads on the floor and their tails above.
The facade has three niches, the central one containing part of a Descending God, and there are two stucco masks on the corners. The portico and shrine have benches, and the vault is shaped like the cross-section of a bottle. Finally, two oratories were built, one at each side of the bottom of the staircase.
Stucco masks wrap round the corner of the main, west-facing facade of the Castle between the two cornices. They have open mouths which bare their teeth, large stylized eyes and feather headdresses.