The Balrog vs The Witch King

[obloquy]

Originally Posted by Gordis

Yes, that is the reason why Glorfindel didn't kill him, obloquy. But you know quite well that Glorfindel was no average Elf. Actually, the reincarnated Elf was quite unique - closer to Maiar in strength.

His reincarnation was relatively unique, but his power was not. Note that he is still never spoken of as one of the greatest of the Eldar. Gandalf was not overly impressed when he explained that Frodo had seen "an Elf lord revealed in his wrath." In any case, the distinction you've drawn between Glorfindel and "the Elves" is a false one: if Glorfindel had slain the Witch-King it would not be unacceptable to say "the Elves killed the Witch-King," so in this case it is also rightly said that the Witch-King fled from the Elves. He did flee specifically from Glorfindel, but Glorfindel was not the most powerful of the Eldar remaining.