Complex sentence: One of the Parademons killed Hyena (the one that Deadshot didn't kill), they also killed General Immortus and Solomon Grundy (comics), most of them were killed when Lex Luthor blew up the teleportation machine.
Split into simpler sentences: One of the Parademons killed Hyena (the one that Deadshot didn't kill). Most of them were killed when Lex Luthor blew up the teleportation machine.