Complex sentence: The death of Shazam was particularly useful, as his various champions then became a tether of power; all Alexander had to do was capture one of them, make them say'Shazam', and they would summon their lightning bolt to power his machine.
Split into simpler sentences: The death of Shazam was particularly useful, as his various champions then became a tether of power. All Alex had to do was capture one of them, make them say'Shazam' and they would summon their lightning bolt to power his machine.