[davem]

Originally Posted by Oblo

Where did this idea that the Barrow Blade was the only thing capable of piercing the WK's "magic" come from?

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 Dunedain 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.

Clearly only a Barrow Blade could have done the job. More interestingly, Tolkien states 'No other blade'. One could read this as meaning it was not only any Barrow Blade that could have done it, but only the particular blade that Merry bore. Its possible that when Tom gave that particular blade to Merry he was laying out his destiny before him. Perhaps it wouldn't even be too mad to suggest that the Blade was what drew Merry to the Pelennor with the Rohirrim. Anyway. Whether it was Merry's blade alone or all the Barrow Blades, we know that they are weapons with specific powers:

"See!" cried Aragorn. "Here we find tokens!" He picked out from the pile of grim weapons two knives, leaf-bladed, damasked in gold and red; and searching further he found also the sheaths, black, set with small red gems. 'No orc-tools these!" he said. "They were borne by the hobbits. Doubtless the Orcs despoiled them, but feared to keep the knives, knowing them for what they are: work of Westernesse, wound about with spells for the bane of Mordor.

I think what it does show is that once again we are not dealing with power vs power. Certainly the man who wrought the Blades was not more powerful than Angmar, yet he was able to create weapons that could destroy him.