Now that the dark side is mentioned, Nine Inch Nails'
"The Becoming" reminds me of the emergence of the Nazgūl (that we know so outrageously few of).
It's a very cold and brutal song about a person who feels that he himself is taken over by something else. The last two lines of the lyrics are repeated several times and in two voices thus adding to that feeling of schizophrenia I connect with the Ringwraiths in their earliest condition.