Massive fantasy dog resting inside a desert cave

Dog enorm colossal , robust dog, a mix of Tibetan mastiff and Caucasian shepherd and Boerboel and pitbull dog and the head of German Shepherd and caucasian shepherd dog and tibetan Mastiff dog, with very thick, robust and muscular legs of a lion's, and with claws and paws and powerful teeth and fangs, with thick fur that covers it's face and head, and intelligent blue eyes, lying in a cavern in a desert with huge dunes in the cliff of an island in archipielag with rock and dunes islands in a blue sea