Complex sentence: Faced with the threat of being forced to become a Justifier himself, Luthor agrees to become Libra and Darkseid's servant, though with help from Doctor Sivana and Calculator, ultimately turns against Libra and forcing him to retreat.
Split into simpler sentences: Faced with the threat of being forced to become a Justifier himself, Luthor agrees to become Libra and Darkseid's servant. With help from Doctor Sivana and Calculator, Lex Luthor ultimately turns against Libra and forces him to retreat.