The Princess takes jabs at the Big One with her spear as you try to make your way behind it. It knows what you are up to, and continues to twist around, keeping both of you in its line of sight.
You eye the creature carefully, watching its movements, timing how long it takes to snap its jaws, swipe with its claws, or lunge forward. You wait for a lunge. It is the easiest to predict and the longest it takes to recover its defensive stance.
The Princess continues to dart forward and back, baiting it. Finally, the Big One seems to get frustrated and lunges forward. You seize the opportunity and lunge forward yourself, aiming low for where you think its heart is. The spear pierces the creature's side and you continue to drive it in deeper. The Big One finishes the lunge motion and stops. For a moment you freeze, fearing that you missed what you needed, and only stunned it. Then it lurches forward several steps and collapses on the ground as its blood begins to pool. It dies quickly thereafter.
Triumphantly, you look over to the Princess, but do not see her right away. After scanning the scene, you find her body against a far wall. The Big One managed to get her with the last lunge. Behind you, you can hear men running up triumphantly. The lizards seemed to sense the death of the Big One and retreated. Standing over the Princess, you can't help but tear up. The war is over, but at a terrible cost.
The End.