“Sauron has yet to reveal his most deadliest servant, the one who will...” – Gandalf the White, The Lord of the Rings: The Return of the King ... Movie Quotes Database

[on the Witch-king]

Sauron has yet to reveal his most deadliest servant, the one who will lead Mordor's armies. The one they claim no living man can kill. The Witch-King of Angmar. [to Pippin] You've met him before. He stabbed Frodo on Weathertop. He is the Lord of the Nazgul, greatest of the Nine. Minas Morgul is his lair.

More from The Lord of the Rings: The Return of the King

Gandalf the White Send word to all our allies. And to every corner of Middle earth that still stands free. The Enemy moves to strike us. We need to know where he will attack next. Aragorn Long have you hunted me. Long have I eluded you. No more. [he holds Andúril up to the palantír] Behold the sword of Elendil! Aragorn My friends... you bow to no one.