Webway - The Black Library: The best hidden of all the realms in the Labyrinth Dimension is the mysterious Black Library, the secret craftworld which contains all the knowledge that the Aeldari have collected about the primal force of Chaos across millions of standard years.To reach this fabled realm, one must court madness itself, travelling secret passages through the Webway, evading the gaze of the horrifying entities that stand guard, and unlocking one of the library's cunningly hidden entrances amid veils of riddle and illusion.The Black Library houses all of the Aeldari's most precious knowledge, and is said to resemble a vast, impossible craftworld that exists only within the Labyrinth Dimension. There is lore here regarding every deadly galactic mystery that the Aeldari of any faction or kindred have ever encountered.The exact shape and form of the Webway is not fully understood by the Aeldari of the present day. Known by some as the Labyrinth Dimension, the Webway has been envisioned by mortal minds in myriad ways. Some describe it as a galactic tapestry of shimmering strands, others a maze of glowing tunnels, or the veins of some vast living entity. All such accounts fall short of the truth, for the Webway defies neat categorisation.It is an elegantly crafted realm located between realspace and the Warp, analogous to the surface of a still, dark pool, or a fine silk veil drawn across something foul. The Webway once spanned the galaxy, even stretching out into the empty, extragalactic void beyond. But those days are long gone. Ravaged by war and catastrophe, many of its tunnels have been torn open or amputated entirely, and a great number of its entrances have been sealed by the Aeldari themselves as a desperate measure to deny their foes access.The Aeldari no longer share its secrets with Humans for the knowledge of the myriad secret ways are considered of the utmost importance to the survival of their threatened species. As noted above, is rumoured that a complete map of the Webway was made many thousands of Terran years ago, which is now kept in the Black Library. This is a bulky, ancient Imperial tome known as the Atlas Infernal. It is an organic, adaptable map of the Webway, dating from before the time of the Horus Heresy. A psychically-negative item, its "pages" were created from the stretched pieces of skin of an Untouchable who had once been an Imperial Sister of Silence, attached to lightweight golden frames.The veins, capillaries, and arteries on the "pages" could reconfigure themselves to show the reader their desired destination within the Webway, being constantly fed oxygen by an intricate regulated pump embedded in the book's spine. Although no longer entirely accurate, the Atlas Infernal shows many secret ways through the Labyrinth Dimension that have since been lost or forgotten.It is the Harlequins who watch over the Black Library alongside its dark guardians, and use its secrets to gain the upper hand in their eternal war against Chaos. They utilise their knowledge of the Webway's hidden paths to outmanoeuvre their foes and strike from unexpected quarters. In this way, whole masques of Harlequins can position themselves in ambush, guaranteeing themselves the element of surprise.Of course, such a system is not perfect, for the Webway has become a broken and dangerous realm. Still, this is little help to the general who suddenly discovers their armies overrun from within, slaughtered by a host of Harlequins before they even realise that battle is joined.