Not specifically the Witch-King, but it was created to fight his forces way back in Angmar, IIRC.
Yes. During the narrative of Fellowship of the Ring, Merry had taken a sword from the Barrow-Downs that was actually a knife that had been forged (and enchanted) by the the Dunedain to be especially harmful to the Witch-King (as well as the other forces that threatened Arnor), although he didn’t know this at the time.
The way that the Witch-King fight went in the book is that Merry effectively crippled the Witch-King with the enchanted blade, allowing Eowyn to land the killing blow. The enchanted nature of Merry’s blade was not mentioned in the movie.
Yes; it was recovered from the Barrow, and forged specifically against him centuries ago.
thanks to Der Tris,Sakuma Drops and Stormcrow
Thats why I always carry extra “Identify Item” scrolls
The obvious choice for most incompetent has to be the Council of Elrond.
“So, we’re agreed then. The Ring must be destroyed, and Frodo shall bear it to Mount Doom.”
“Excellent. Gandalf has an in with Gwaihir the Eagle. He and his fellows can carry Frodo there, and we’ll be done with this unpleasantness in a matter of a couple of days.”
“Oh, no, no. Can’t have Eagles crapping all over the Last Homely House. Frodo should walk to Mount Doom.”
“Walk?”
“Yes, walk. Good exercise, and much more sporting. We’ll send some friends along, and they can all sing songs along the way.”
“But they’ll have to cross through Moria! They could get killed in there.”
“That’s a little bit racist, you know. Besides, I’ve heard the Dwarves have been redeveloping Moria.”
“They’ll have to find their way into Mordor!”
“Hobbits are natural burglars. Gandalf said so.”
“But the Eagles could --”
“NO EAGLES! Start walking!”
Trust me, you really don’t want an Artifact of Evil that also happens to be a small shiny object anywhere near giant birds.
Thor would disagree about that last part. 
I’m going to do some redaction criticism here: the epithet Wormtongue was the invention of Gondorian scribes. Theoden, Stormcrow, et al all referred to and addressed him as simply Grima.
Der Trihs - That particular quote about the passing of the witch-king always gives me chills.
Chuck Norris simply walks into Mordor.
No, just no.
Sauron was well aware of the Eagles being associated with Manwë and would be especially on the look out at all times for spying eagles. Also the Eagles did not have the ability to fly the Hobbits all the way to Mount Doom, they still would have had to get very near to Mordor to attempt it.
It was not the original plan to go through Moria, put rather over Moria. That did not work out well. You know why they could not go around Isengard down the Greenway already.
Gandalf planned to lead the Hobbits in Mordor. This is the Wizard that snuck in and out of Dol Guldor while Sauron was in residence. He was pretty good at these things.
Now Elrond wanted to send Glorfindel with them. The Elf that the Witch-King was gravely afraid of and had previously killed a Balrog but I believe Gandalf feared that taking Glorfindel with them would have been like lighting a beacon that said, “We have the Ring and we’re coming to get you.”
Stealth and a desperate gamble was what Gandalf tried in the end. While I think they should have taken horses at least as far as the pass, stealth is what gave them some hope as opposed to no hope.
Don’t get me started on the Glorfindel subject! They’ll leave him at home, but the rest of the Company is fine, because of course someone like Gandalf is totally inconspicuous. The real reason is that Gandalf didn’t want someone else giving orders and looking smart. Gandalf is a control freak.
Theoden knew that your deputy is always going to be resented. I read something like that in The Caine Mutiny (the novel by Herman Wouk), when Captain Queeg says how the exec on a Navy ship can’t be expected to be making a lot of friends.
*“So passed the sword of the Barrow-downs, work of Westernesse. But glad would he have been to know its fate who wrought it slowly long ago in the North-kingdom when the Dúnedain were young, and chief among their foes was the dread realm of Angmar and its sorcerer king. No other blade, not though mightier hands had wielded it, would have dealt that foe a wound so bitter, cleaving the undead flesh, breaking the spell that knit his unseen sinews to his will.” *
This has always said to me that Merry struck the killing blow. Eowyn’s frontal attack on the witch-king distracted him, allowing Merry to get close enough to do the deed. I can’t see any argument that can plausibly credit Eowyn with the kill.
Well Gandalf the Grey was cloaked to the eyes of the enemy is my reading on what little we know of the Five Wizards. As I mentioned, he came and went in and out of Dol Guldor without Sauron knowing it.
I suspect Gandalf the White was not so cloaked. I believe when Erü sent him back it was pretty much as a full powered Maia. Remember, he claimed no weapon of Aragorn’s, Gimli’s or Legolas’s could have hurt him and he wasn’t quite Gandalf anymore. I believe he was closer to Olorin of the West then Gandalf the Grey at that point.
I agree. Éowyn could not have killed the Witch-King. At most she could have dis-incorporated him if you will. It was Meriadoc’s blow with the enchanted blade that allowed Éowyn’s great blow to finish off the Witch-King. But anyone at that point should have been able to deliver the final blow, but prophesy made her the perfect person and of course provided a great distraction when she took off her helm to allow Meriadoc to get the drop on the Witch-King.
In the safety industry, a term of art for these sorts of things is “administrative controls.” They have kind of a bad reputation because they can be ignored by fallible humans.
Hmmm, so is that why Galadriel liked him so much?? 
He was immune to any normal attack until the magic blade broke the spell that made him immune, which Merry did. Merry’s attack would not have been fatal on a living person due to where he struck. Eowyn then finished him off with a mortal blow.
Merry and Eowyn were clearly in the same raid group, so both gain experience for the kill. Sadly, Tolkien was sloppy and did not properly itemize the Witch-King’s loot table, so nothing but a few silver and a grey mail armor piece (vendor fodder) dropped.