Why is he called the Witch King?

What is the ring of the Witch King of Angmar?

I don't know how canonical that is. But this is a ring that is meant to be.

http://img2.wikia.nocookie.net/__cb20121002111201/lotr/images/a/a4/Witch_King_of_Angmar_as_king.png

http://www.aliexpress.com/item/New-Arrival-Nazgul-ring-Witch-king-of-Angmar-Ringwraith-The-Lord-of-the-rings-free-shipping/1002475542.html

The Witch King doesn't have a name (we don't know if I'm not mistaken) which probably means his ring wouldn't ring either. In addition, he did not control himself and it was believed to be invisible, which means that there were few chances that he and his ring were named by himself.

I don't think he was special enoughto be named and given a name.

The nine rings for mortal men were the ones that were divided among those evil men who were doomed to become the Nazgûl, the Ringwraiths. These ring bearers held rings controlled by Sauron because they became evil servants of his. No one is specifically mentioned in the entire Lord of the Rings, except for their leader, the Witch King of Angmar.

"Nine for mortal men condemned to die"

What I mean by that, I don't think he's special enough, is that I don't think he was healthy enough or even that important as a character or person. All he was was a tool for Sauron and a tool for the author for literary purposes. I mean he was doomed to die.

From the same side.

According to the nature of man and his innate inability to withstand evil, one by one they fell under Sauron's constant control and became spirits who only performed Sauron's commandments. They remained permanently invisible

The Ringwraiths are supposed to be named somewhere, but that is not canon.

The early Middle-earth role-playing games name the eight other ringwraiths, Er-Murazor (the witch-king of the Númenórean race), Dwarf, Ji Indur, Akhorahil, Hoarmurath (Númenórean), Adunaphel (Númenórean), Ren and Uvatha, but none of these names is called Canon viewed, and the idea of ​​a female ringwraith in particular, is unlikely in the context of Tolkien's work, although it is possible since three Númenórean queens ruled under their own power

One

In the role-playing game he is called Er-Murazor - but not quite canonically.

ElendilTheTall

The second in command after the Witch King is called Khamûl. He is described as an Easterling. It is in Unfinished tales , The hunt for the ring.

Pobrecita

@ElendilTheTall I don't know how this applies to my answer as it is not about the Witch King. But thanks anyway, if you tell me how to apply, I'll add it to my answer if my information is wrong.

ElendilTheTall