Step 1: Understanding the Maharaja's situation.
The anxiety of the Maharaja, from the story "The Tiger King" by Kalki, reaches a fever pitch when he learns that he must kill 100 tigers to fulfill the prophecy. Despite his efforts, he faces an increasing sense of fear and pressure as the number of tigers he kills approaches the target.
Step 2: Identifying the critical point.
The Maharaja's anxiety reaches its peak when he realizes that he has unintentionally killed a large number of tigers and that the final tiger, which he needs to kill, is eluding him.
Step 3: Conclusion.
Thus, the Maharaja's anxiety reaches a fever pitch when the last tiger, which he needs to kill to fulfill the prophecy, remains elusive, causing him immense stress.
Final Answer: \[ \boxed{\text{The Maharaja's anxiety reached a fever pitch when he realized that the last tiger he needed to kill to fulfill the prophecy remained elusive.}} \]