Complex sentence: The last of fought with ferocity and courage for they were continuing to retaliate with their spears and catching the Romans javelins and throwing them back at them, the Nervii hadn't used any other projectile type weapon except for the spear.
Split into simpler sentences: The last of them fought with ferocity and courage for they were continuing to retaliate with their spears and catching the Romans javelins and throwing them back at them. The Nervii hadn't used any other projectile type weapon except for the spear.