“Thee” and “thou” in “The Lord of the Rings”

[Galadriel55]

I came across another quote that I don't believe was mentioned here before:

Then Glaurung stirred for the last time ere he died, and he spoke with his last breath, saying: "Hail Nienor, daughter of Hurin. We meet again ere the end. I give thee joy that thou hast found thy brother at last. And now thou shalt know him: a stabber in the dark, treacherous to foes, faithless to friends, and a curse unto his kin, Turin son of Hurin! But the worst of all his deeds thou shalt feel in thyself."

~Of Turin Turambar, The Sil, as well as The Death of Glaurung, COH.

Glaurung could easily be talking down to Nienor, like he did before to Turin. After all, he knows that he dies victorius: he succeeded in demolishing the family. Or, maybe, he's being sarcastic and addressing Nienor like a friend and equal. Or maybe he forsees that they are equal by their death. It's a funny thing how they all died in basically the same place, Glaurung, Nienor, Turin, and Gurthang. And later Morwen.