Complex sentence: The Anti-Monitor waits for Alex Luthor to reopen the portal between the positive and antimatter universes, capturing the heroes, but a magically empowered Spectre creates an energy overload which shatters space and time.
Split into simpler sentences: The Anti-Monitor waits for Alex Luthor to open the portal between the positive and antimatter universes, capturing the heroes. The Spectre (supported by Earth's magically powered heroes in the positive universe) battles the Anti-Monitor, creating an energy overload which shatters space and time.