Complex sentence: By the end of the series it is revealed Kazuki is a made out of fragments of Saryuu left behind as an imperfect copy, and he ultimately reaches his manifest destiny of becoming a perfect copy of Saryuu.
Split into simpler sentences: By the end of the series it is revealed Kazuki is an imperfect copy of Saryuu made out of fragments left behind. He ultimately reaches his manifest destiny of becoming a perfect copy of Saryuu.