Weathertop: Reply to Aaron
John R.

Aaron asks, why did the Nazgul run off after stabbing Frodo at Weathertop, since they appeared to have Strider and the Hobbits helplessly in their grasp?

I recall that Strider himself expressed puzzlement that the Nazgul disappeared.

There are several possible factors in the Nazgul's decision to bide their time.   First, the Nazgul were surprised to learn that the Hobbits held Westernesse daggers, which were anathema to them.  All the Nazgul (except the Witchking) stopped in their tracks when Frodo pulled his short sword.  Why imperil their immortality by taking an unnecessary risk with those daggers?  The Witchking kept coming because he was overly confident, that "not by the hand of man" would he fall, incorrectly assuming that Hobbits did not count.  He shrieked when Frodo's blade cut through his robe.

Second, the Nazgul knew nothing about the nature of Hobbits.  They may have been supremely confident, from eons of experience, that the knife wound would quickly kill off little Frodo and expose him to their world.

Third, the Nazgul (oddly) feared fire, so may not have been able to tolerate being around the campfire and Strider's flaming brand.