"Time" is the axis that runs throughout, carrying the protagonist's life trajectory spanning hundreds of thousands of years, from the wild wilderness of the Paleolithic Age to the steel jungle of the Information Age. Time is his only constant travel companion and the sharpest carving knife.
"Cast bones" is a metaphor for the essence of his existence - over the long years, his bones not only supported his immortal body, but also engraved the genes of civilization. The patterns on each bone are the marks of a certain era: animal bone carvings from the Paleolithic Age, casting smoke from the Bronze Age, battlefield rust from the Iron Age, machine oil stains from the Industrial Age... Time has forged the fragments of civilization into his bones and blood, making him a walking living fossil of human history.
