The Gate of Horn is one of the two gates in the centre of Arcadia. It is through this gate that Sidhe fae souls are incarnated.
The Gate of Horn was created by Nocker, who crafted it from horns taken from the skeleton of Sidabras. He made the gate, wishing to bring forth a power which would allow him revenge on the Trolls who had exiled him. Rather than a servant to do his bidding, however, the House Founders came through. It was Lord Dougal who splintered a shard off the gate when he struck it with his hammer. After the Sundering no longer did Sidhe emerge, but rather the twisted Fomori.