The craftworld of Iyanden was once the largest of all the Eldar craftworlds and its people the most numerous. Iyanden was the scene of the Eldar's most dramatic encounter with the hive fleets of the Tyranids, the all consuming menace whose advance across the galaxy has since consumed hundreds of human worlds. Though the Eldar finally repulsed the invaders, the cost was bitter. Their once-proud world stood in ruins, and four-fifths of the inhabitants lay dead or dying in its shattered halls.

Drifting through space, the craftworld was powerless to avoid the sudden onslaught of Tyranids. Wave upon wave of merciless hive warriors swept over the craftworld, each eventually beaten by the Eldar, but at the cost of thousands of lives. The Tyranids' psychic warp blockade disabled the craftworld's access to the webway, preventing the Eldar of Iyanden summoning aid from other craftworlds. As a last desperate gambit the Eldar of Iyanden decided to wake their dead to repel the invaders. All the ancient spirit stones were plucked from their resting place and installed into metal fighting constructs called Wraithguard.

These Ghost Warriors turned the tide of battle, and soon the Tyranids were beaten back, but it was a hollow victory for Iyanden. The craftworld and its people had been dealt a blow from which they would never recover.

Since their awakening most of the Iyanden Ghost Warriors gradually drifted back into the slumber of death and their spirit stones were re-implanted into the Wraithbone core that forms the framework of the craftworld. However, some of the Wraithguard still linger in wakefulness, driven by anger and a burning desire for vengeance. These heroes of long ago wait for the call of battle and a chance to vent their wrath upon the enemies of their race.

The colour associated with Iyanden is yellow and the symbol of Iyanden is the Shrine of Asuryan, the oldest and wisest of the Phoenix Kings. Most Iyanden troops have yellow uniforms with details in a contrasting blue. Their vehicles also have yellow colour schemes.