The castle of Karos (Kasteli) belongs to a more advanced phase of the prehistoric settlements of Kaonia. It is located above the old village of Qeparo, in the place called “gradishta” and is built on a high rocky hill 450 m located 3.5 km from the sea. The Karos fortification system consists of three rows of walls and a front wall. The outer wall of the enclosure is 340 m long, has the shape of an arch that follows the terrain configuration with edges closing at the edge of the abyss. On its eastern side is an entrance, which is the only one in the whole outer perimeter wall. The second perimeter wall with a perimeter of 225 m extends almost parallel to the first and encloses a smaller area. There is a narrow entrance. The third perimeter wall in the form of a semicircle, at a length of 40 m and a radius of 13 m, closes the top of the hill. Even in karos the planimetric concept is based on the arched line that forms the wall in adaptation to the terrain. Entrance No. 4 is well preserved with a width of 1.5 m, height 1.70 m and length of the corridor 5.70 m. The fortification system in Karos was realized in two different construction periods. In the beginning was built the fortification that includes row II of the walls, which we call Karos I. The resemblance of Karos 1 to Badhr, as from the technique of building the walls and ceramics, dates it to the Late Bronze Age. Phase two belongs to the Early Iron Age. Surrounding walls vary in width and height according to terrain configuration. They range from walls 2-3.5 m wide to 4 m high and up to 2 m high. The walls are built of large and medium unworked stones, placed in the dry. There are two sides and for the construction of the exterior large stones have been chosen, which are placed in the longest part inside the wall, which increases the resistance in the sloping terrain, the joints do not fill and create gaps. This is how the first phase is built. In the second phase, the facade of the wall is built with slabs that fit well, so as not to leave gaps, the stones are worked with a hammer.