The horn is six feet (1.83 meters) long. It is made from the horn of what must have been an enormous dragon. It has a black gleam, and is banded with red gold and Valyrian steel. When touched, the horn feels warm and smooth. Its surface is shiny and reflective, though the reflection depicted is somehow twisted. The bands of the horn are covered by strange writings, Valyrian glyphs. When the horn sounds, the glyphs glow red-hot, and then white-hot.
A Feast for Crows
When the ironborn gather to elect a new King of the Isles and the North at the kingsmoot on Old Wyk, Euron Greyjoy displays Dragonbinder, a dragon horn. Euron claims to have sailed the Smoking Sea, and found it amongst the smoking ruins that were Valyria. However, according to a semi-canon source, Euron took the horn from four warlocks from Qarth, whose ship he seized when they went in search of Daenerys Targaryen after the destruction of their House of the Undying.
The horn's noise silences all at the kingsmoot, and ends the possible fight between the supporters of Euron's brother, Victarion, and his niece, Asha Greyjoy. The horn's noise sounds like the screaming of a thousand souls, and it seems to listeners as if their very bones are aflame and searing their flesh from within. Cragorn, the man who blows the horn for Euron, collapses with blisters on his lips, and the tattoo he has of a bird on his chest is bleeding.
Euron wins the kingsmoot by promising the ironmen that they will conquer Westeros with dragons. When Asha argues that there are no more dragons, Euron tells her that there are three, and he knows where to find them. He does not mention that the dragons belong to Daenerys.
A Dance with Dragons
Euron sends Victarion to Meereen to bring Daenerys Targaryen back to him, and gives Victarion the horn. Victarion has the horn with him aboard the Iron Victory. According to Moqorro, a red priest, the Valyrian glyphs on the horn read, "I am Dragonbinder ... No mortal man shall sound me and live ... Blood for fire, fire for blood."
Moqorro says whoever blows the horn will die, but any dragons that hear will obey the horn's master. The red priest says Victarion must be made the horn's master, and he must claim the horn with blood.
The Winds of Winter
This information has thus far been released in a sample chapter for The Winds of Winter, and might therefore not be in finalized form. Keep in mind that the content as described below is still subject to change.
When Victarion and the Iron Fleet arrive at Slaver's Bay, Victarion still has the horn with him in his cabin. Some of the Iron Fleet arrives at the bay of Meereen, just as the second siege of Meereen is about to resume.
Bright and baneful was its voice, a shivering hot scream that made a man's bones seem to thrum within him ... It is the horn of hell.—thoughts of Aeron Greyjoy
That horn you heard I found amongst the smoking ruins that were Valyria, where no man has dared to walk but me. You heard its call, and felt its power. It is a dragon horn, bound with bands of red gold and Valyrian steel graven with enchantments. The dragonlords of old sounded such horns, before the Doom devoured them. With this horn, ironmen, I can bind dragons to my will.—Euron at the kingsmoot
- A Dance with Dragons, Chapter 63, Victarion I.
- A Dance with Dragons, Chapter 26, The Wayward Bride.
- A Feast for Crows, Chapter 19, The Drowned Man.
- A Dance with Dragons, Chapter 10, Jon III.
- George R. R. Martin's A World of Ice and Fire, Qarth.
- A Dance with Dragons, Chapter 19, Davos III.
- A Feast for Crows, Chapter 29, The Reaver.
- The Winds of Winter, Victarion I
- The Winds of Winter, Tyrion II