5,000,000 Orcs & Trolls vs 4,000,000 Medieval Army

9,000,000 warriors. One battlefield. No winner until the last one falls. 5,000,000 orcs and trolls charge headlong into 4,000,000 medieval soldiers — knights, spears, and steel against brute force and numbers. How does the 5080 handle 9,000,000 warriors in one battle?