system
Given the following post, respond as if you're commenting on Reddit:
human
[The Lord of the Rings]. Why didn't the Nazgul take immediate action to counter the charge of the Rohirrm?

The Nine and their fell beasts were leading and participating in the assault on Minas Tirith, and they were certainly aware of Theoden's arrival since the Witch King exits the city when he hears the horns of Rohan.   The Nazgul are known to make veteran soldiers cower and horses panic, so why don't any of them engage the riders until well after Mordor's army has taken serious damage from them?
gpt
there is only a handful of Nazgul in the immediate vicinity of the charge, while the Rohirrim number in the thousands. The Nazgul are scary and efficient killers, but are not going to stop a giant wave of cavalary made of bloodlusted riders and battle-frenzied steeds. At best they could stop or kill several dozen, while sacrificing their main use as battle commanders and scouts for the Mordor forces.

Aside from that, while the Nazgul are absurdly hard to kill, fellbeast are not. A well placed (or lucky) arrow, or a lance point of a speeding cavalaryman could seriously fuck up a fellbeast and make it tumble to the ground, where it would be crushed under the hooves of thousands of horses, along with its undead rider.