Complex sentence: To gain control, Mandible publicly portrays Z as a war criminal who cares about himself before promoting the glory of conformity and promises them a better life which he claims to be the reward of completing a "Mega Tunnel" planned by himself.
Split into simpler sentences: To gain control, Mandible publicly portrays Z as a self-centered war criminal. Mandible promotes the glory of conformity and promises them a better life through the reward of completing a "Mega Tunnel" planned by himself.