The church of Agios Nikolaos Trikabanos (with three bells) lies at the northern reaches of Kastania. The domed cross-vaulted church dates to the 14th-15th century, while the barrel-vaulted narthex at the west is slightly later. A round apse projects at the east. The dome has a square drum with rounded corners. The church was built with rubble masonry, with very few brick fragments used in the joints. Worth noting is the layout of the south side of the narthex, with three blind arches, an arrangement reminiscent of the narthex of the nearby Agios Petros. The wall paintings in the nave date to the 15th century, while earlier ones are preserved in the narthex.