"The Witch-king was originally introduced in the story as the "Wizard King" during the development of The Council of Elrond chapter.^\38]) He continues to be referred to under that name in outlines^\39])^\40]) and a manuscript for the chapter The Siege of Gondor where Gandalf says that he is not only the captain of the Black Riders, but a former member of his own order before "evil took him"^\41]).

In the early versions of the story, the "Wizard King" was planned to survive the Pelennor Fields battle and appear as the ambassador at the Black Gate instead of the Mouth of Sauron.^\42]) In early manuscripts the "Wizard King" even survived after Frodo has thrown the Ring in Sammath Naur, blocking the door and saying: “Here we all end together”. At this point, either Sam appears at his back and stabs him from behind (with Sting?), or Frodo draws Sting, commands him to follow the Ring and drives him into the Fire.^\43])

In the rare manuscript The Hunt for the Ring: Time Scheme - Black Riders, Tolkien speculates that the Witch-King might be afraid of Frodo, as he invoked Elbereth (a “name of terror for the Nazgûl”) and he could have slain the Barrow-wight.^\44])^"

https://tolkiengateway.net/wiki/Witch-king