Battle of Biel-Tan - Prelude to Conflict: Solar months before Yvraine was chosen as the high priestess of Ynnead during the Night of Revelations in Commorragh, secreted in vaults of black wraithbone within Craftworld Ulthwé, Eldrad Ulthran had foreseen much of that which was coming to pass.Following the ripples in the fabric of the future that he himself had caused upon the crystal moon of Coheria during the Battle of Port Demesnus, he saw a new force rising, embodied in one called the Daughter of Shades. She alone held the key to Ynnead's ascension, and the cosmic upheaval Eldrad and Kysaduras the Anchorite had long predicted.Pursuing Yvraine's thread of fate in his meditations, Eldrad deemed that there was no haven more likely to take this living phenomenon into their heartlands than Biel-Tan. Even then, Eldrad had seen the Reborn gladiatrix and the ruling castes of the craftworld bound together on an altogether deeper and more spiritual level.Another nexus point of destiny approached, the skein of fate knotted and tense around it. As he refined his divinations, Eldrad had seen the rune of the Night Maiden circled by the Fall from Grace, both in turn orbiting the heraldic rune of Biel-Tan itself. Ominously, the stylised heart that sat within the craftworld's iconic rune had smouldered and turned black. Such was the price of progress.The High Farseer of Ulthwé had sent a psychic signal across the vastness of the Webway, in doing so despatching the only agents he could truly trust to work to a greater goal. So it was the Masque of the Midnight Sorrow had made haste through the Webway to Biel-Tan, their intent to pave the way for Yvraine's arrival.Ildraesci Dreamspear performed an elaborate bow, his arms wide. The Autarch Meliniel replied with a stylised salute. Both gestures were remarkably tense for warriors of such grace. With the Biel-Tani Autarch were Dire Avengers, their weapons held lightly at their sides. Alongside Dreamspear, a dozen Harlequins stood in exaggerated postures of relaxation."Unusual, to arrive unheralded in such a fashion," said Meliniel casually. "Though it is perhaps the way of the Midnight Sorrow to embody the void-zephyr, taking or leaving as they please.""Uncommon, for an armed escort to welcome ambassadors," said Dreamspear. "In these dark days, we all walk shadowed paths.""As you say," nodded the Autarch. "Let us ensure they do not lead us astray. An act of provocation, such as Cegorach's theft of fair Isha's jewels, could be considered an act of open contempt.""Provocation? Some say Cegorach's act was one of desperation, committed in pursuance of a greater victory," said Dreamspear."Of course. Though in times of war, lethal mistakes are made.""Let us hope they do not lead to unnecessary tragedy in the final act. Only a fool is deaf to the words of a prophet.""These words you speak of," said the Autarch, turning to pinch the stem of a crystal rose and move it to catch the light, "do they concern the God of the Dead, perchance? Lathriel believes so.""Indirectly, they do. They concern all of the Aeldari, past, present and future. But you, most of all," he said. "Your people, and you.""And so your troupe, known defilers of the Dome of Crystal Seers, choose to breach a latter-portal rather than obeying the unwritten codes." The Autarch shifted, his body language speaking volumes."We had little choice. Ichor still dries on our blades. The children of She Who Thirsts already know of the Daughter of Shades.""So you risk doom to force our hand," said the Autarch. "You endanger only yourselves. They cannot penetrate the wards.""No, no," laughed the Harlequin hollowly, his mask becoming the coal-eyed visage of Khaine's Avatar as he made the sign of the black key. "They seek not to attack Biel-Tan directly, but via a threshold world. From there, a new tapestry of fate will unfold.""And have your divinations told you which world the she-daemons intend to breach?" said the Autarch.By way of answer, the Harlequin reached out and opened the palm of his hand. The Autarch looked down at the rune held there for a long moment before gesturing to his Exarch. "Gather the Swordwind. Inform Lathriel. We strike at dawn." He turned on his heel and left the audience chamber without a sound.Though the Masque of the Midnight Sorrow had lately garnered a reputation as self-centred thieves and bearers of ill-tidings, the message they brought to Biel-Tan was of such dire import it could not be ignored.The Autarch Meliniel consulted with the craftworld's High Farseer and her sister, Lathriel, even as the craftworld's Aspect Warrior warhost -- known as the Swordwind -- was mobilised for war.Lathriel's own runic divinations, when carefully interpreted with the Harlequins' message in mind, spoke of a baleful truth. Much like Eldrad, she saw a fork in the destiny of her people, one route leading to blazing fire -- the sign of the Rhana Dandra, the End of Days -- whilst the other led to a darkened veil and the sound of a mourning bell. The implications were staggering.Perhaps the whispered notion of Ynnead's ascension could stave off the Eldar's destruction for a time, and maybe even calm the Warp Storms ravaging the galaxy. The newcomer the Harlequins spoke of was central to this concept, bound tightly to the runes of the Great Enemy and Biel-Tan itself. It was likely the agents of Slaanesh too were aware of the importance of the interloper, this Daughter of Shades, and intended to seize her themselves.Until now, the runes of warding that protected the craftworld had made the idea of a daemonic incursion the stuff of nightmares, not reality. With Empyrean tempests raging across the Segmentum, however, there was a chance of a Webway breach.Should a host of Warp-spawn set foot upon the craftworld, the sheer magnitude of the disaster that would follow did not bear thinking about. A full daemonic invasion could see the craftworld lying in ashes, never to recover.The Masque of Slaanesh was well aware of this opportunity. She had learned of a route of ingress to Biel-Tan -- a long-sealed Webway tunnel that led from an abandoned extremity of the craftworld to the gates of the Exodite Maiden World Ursulia.