Complex sentence: The Kempeitai ran extensive criminal and collaborationist networks, extorting vast amounts of money from businesses and civilians wherever they operated, they also ran the Allied prisoner of war system which treated captives with extreme brutality, never showing mercy or other typical human empathic tendencies.
Split into simpler sentences: The Kempeitai ran extensive criminal and collaborationist networks, extorting vast amounts of money from businesses and civilians wherever they operated. They also ran the Allied prisoner of war system which treated captives with extreme brutality, never showing mercy or other typical human empathic tendencies.