Unicorn Gate

The Unicorn Gate guards the longest and most treacherous of the mountain passes. As a result, it has seen less conflict than its sister fortresses -- even the most determined of Dark Elf attackers see little purpose in breaching the Unicorn Gate simply to fight their way through the Harpy- and Cockactrice-haunted ravines that lie beyond. For all this, the garrison of the Unicorn Gate are no less tested than those of other strongholds, for they are under constant attack by the denizens of the very pass they guard. Thus have their archers earned a reputation for quick eyes wits. After all, walls are of little defence against winged adversaries and, once a Harpy is within a spear's length, the battle's outcome is already in doubt. It is for this reason that the Unicorn Gate underwent substantial modification during the reign of Bel-Korhadris, adding several dozen outrigger towers from which keen-eyed archers could scour the walls in the event of a Harpy attack.

The greater part of the Unicorn Gate's garrison has always been drawn from the warriors of Ellyrion, who maintain the traditional blue and magenta heraldries of that kingdom.

The position of the Unicorn upon the shield indicates to which of the seven great bastions of the fortress the soldier is assigned.

Source

 * Warhammer: Uniforms & Heraldry of the High Elves -- pg. 38 39