Rescue the Cat

How does the 20th level warrior defeat the giant, heavily muscled rock troll?  It is thirty feet tall, has blade-like claws and a maw of shark-like teeth.  Does he make four attacks per round and half of them are critical hits?  No, he leaps fifty feet into the air and cleaves the troll's thick magically durable skull with his two hundred pound sword! That is how fantasy combat works in Cambrelara…