Complex sentence: Tarzan goes on to help the British in the battle in various ways, including setting the lion loose in the enemy trenches, and kills von Goss, another German officer involved in the attack on the Greystoke estate.
Split into simpler sentences: Tarzan goes on to help the British forces in various ways, including setting the lion loose in the enemy trenches. Tarzan later kills von Goss, another German officer involved in the attack on the Greystoke estate.