Nazgûl by Alan Lee. A portrait of the Witch King leading his armies from Minas Morgul.
All the host was clad in sable, dark as the night. Against the wan walls and the luminous pavement of the road Frodo could see them, small black figures in rank upon rank, marching swiftly and silently, passing outwards in an endless stream. Before them went a great cavalry of horsemen moving like ordered shadows, and at their head was one greater than all the rest: a Rider, all black, save that on his hooded head he had a helm like a crown that flickered with a perilous light. Now he was drawing near the bridge below, and Frodo’s staring eyes followed him, unable to wink or to withdraw. Surely there was the Lord of the Nine Riders returned to earth to lead his ghastly host to battle? Here, yes here indeed was the haggard king whose cold hand had smitten down the Ring-bearer with his deadly knife. The old wound throbbed with pain and a great chill spread toward’s Frodo’s heart.
—The Two Towers, Book IV, chapter VIII, “The Stairs of Cirith Ungol.”