Here’s the final design. Lemme know if the image is too large, and I’ll see what I can do. There were issues with loss of detail.
EDIT
Here’s the backstory, and a HUGE THANKS to Samurai - who basically thought it up and wrote it into words with his vast knowledge of Tolkien-lore. He’s the man.
In the fourteenth century of the Third Age of the Sun, in Middle-earth there again arose the nine servants of Sauron the Ring Lord. The foremost among them came to the north of Eriador, where he made the kingdom of Angmar in Carn dûm. With legions of Orcs and Hillmen of the Ettenmoors, this Nazgûl lord, who was at that time called the Witch-king of Angmar, waged constant war for six centuries against the Dúnedain of Arnor.
In the year 1974 of the Third Age, the last city of Fornost fell to the might of the Witch-king. The Witch-king’s possesion of Arnor was brief, for his army was defeated by the Elf-lords Círdan and Glorfindel and by Eärnur, the king of Gondor, at the Battle of Fornost. During the battle at Fornost, the Witch-king went abroad on the field upon a steed gifted to him by Sauron. This beast was called “Vantanyérë”, the walking grief, and horror went out before it like a chill wind. Its speed was much more than that of a horse, and it went about the field leaping great distances. Where its foot struck the earth was left a grey blight and all that was green turned brown and withered against its breath. Any men who assailed it were made to shrink away in weakness as if old age had taken them and a cold numbness restrained their limbs.
In earlier times, Vantanyérë bore Sauron away in secret from the wrath of the war-host of Valinor and the ruin of Beleriand in the War of Wrath at the closing of first age. It escaped death again in the War of the Last Alliance when it fled Mordor into the Ephel Dúath and then into the north. When the Witch-king established his throne at Angmar, by the will of Sauron, Vantanyérë found his way to him and became the chief of his stable. The beast’s end was met in the battle of Fornost by the hands of Glorfindel who had impaled him upon elvish spear as the Witch-king rode forth to run him down on the gateway bridge. Its death was slow, and it continued to rage until the last of its breath was gone. Never since that time had a beast in likeness to Vantanyérë walked the lands of Middle Earth.
Near the closing of the third age, remembering his defeat, the Witch-king dreaded Glorfindel and would not flee to the riverside, even when faced with the charging waters of the river Bruinen and the ringbearer close at hand.

-aaron