[Legate of Amon Lanc]

Originally Posted by radagastly

There seems to be a similar, though lesser, capacity to enslave mortals inherent in the Morgul-blade as is inherent in the Nazgul rings (or actually, became inherent when the One Ring was created. I'm sure Celebrimbor did not create the Rings with the intention of enslaving mortals.) Aside from their common inventor (Sauron) might there be any connection between them? What I mean is, the Nine enslave their bearers because they are slaves to the One. How does a Morgul-blade enslave? It's unlikely the blades were forged with the power of the One, since that was either in the Anduin, under the Misty Mountains with Gollum or in Bilbo's pocket (unless the blades date from the second age. Anyone know?) Could they have been forged with one of the Nine, or whatever are left of the Seven? or are they a seperate technology?

I'll start from the back. I believe the Morgul-blades are "modern", 3rd-age thing, because they are "Morgul-blades", which implies that they were made in Minas Morgul, that would be in the 3rd millenium of the Third Age. Only it could be that "Morgul" here is just the Elven word that means simply "sorcery" or "witchcraft", but personally I think not.
Anyway, to the main question. "How does a Morgul-blade enslave?" I believe the process is totally different from how the Rings enslave. The Morgul-blade, so to say, slowly kills you. The Ring just possesses you and fading is just a side effect, but the Morgul-blade chills you and makes you fade. The splinter traveled to Frodo's heart, if it pierced it (as it was the original intention, anyway), he'd be dead, technically, but the will of the Ringwraith (or Sauron) would possess his body (or "shadow", to be precise in terminology, since he'd enter the Wraith-world at that moment). There's something like a thin line between the seen and unseen and you pass it for example when you have the Ring on; and so Frodo would be trapped in this world forever as the Ringwraith are, seeing everything dim as they do, and his body would have just disappeared for the others (as if he were invisible). That's at least how I imagine it, I may be wrong. I imagine it the way that his brain "freezes" and his own personality is "doused" and the Ringwraith then could possess him. Technically, the result is the same as when he is possessed by the Ring, but the way is, I believe, somewhat different.

Originally Posted by radagastly

And what of the Barrow-wight? He is presumably the Ghost Prince of Cardolan, is he not? The enemy of the Witch King of Angmar in life. What made him a ghost, instead of passing beyond the circles of the world? Would an earlier Morgul-blade, if used, have the power to trap his spirit in his grave? Just how powerful could they be?

I believe this has nothing common with a proto-Morgul-blade, though I believe if something similar happened, the result would be a creature maybe weaker, maybe almost as strong (depending on how powerful it was in life) as a barrow-wight. However, as far as I know, the barrow-wights were NOT the spirits of Dúnedain! That's I believe very important thing many people are confused in: in Middle-Earth, the spirits of Men leave their bodies and go beyond the Circles of the World, unless something very strange happens. The only folks who were really "ghosts" were the Men of Dunharrow, and that was for their unfulfilled oath and the curse laid upon them by Isildur. But the Dúnedain were of good heart and there was no reason for their spirits to remain in the world (as far as I know there's nothing like the "vengeful ghosts" who remain on the earth because they were murdered and wait for "satisfaction" or whatever), unless the Witch-King trapped them with some necromancy; however even these things are not said in the canon and as far as I know, even in HoME there is just a speculation that Sauron might have trapped some Elves' spirits in Dol Guldur - but that speaks of Elves and not about Men; Men are quite a different sort and I'm not sure how much power Sauron would have over them after their death (just a side note, the Nazgul were not dead, but "faded to shadows"; had they died first, Sauron would probably have no power over them, they'd just leave the Circles of the World like everyone else). The Barrow-wights, to return to the original thought, were some "evil spirits" (who knows what; maybe some of these Necromancy-trapped spirits or the same sort of "spirits" that, as we read in the Silmarillion, were summoned to inhabit the bodies of Ents and Eagles).

Originally Posted by LotR Appendix A; The North-kingdom and the Dúnedain

It was at this time that an end came of the Dúnedain of Cardolan, and evil spirits out of Angmar and Rhudaur entered into the deserted mounds and dwelt there.

So, technically: the Barrow Frodo was in belonged (probably) to the last prince of Cardolan, but what lived inside was not some corrupted ghost of the prince, but a creature possessing his tomb, his treasures and his bones.