"'' how am i supposed to do that ? '' esephris asked . ka 's voice answered as if he had really heard him , '' find the skulls that are scattered throughout time and bring them to the center of atli mountain . all thirteen skulls must be properly placed in order to drive the darkness out . you must practice and learn to use your gift , transfer your soul to other times and civilizations , and find the _ ..." What is the word in the blank space (_)? The answer is
skulls