Slaanesh - Birth: If the legends are to be believed, there was one being born into the Warp from the depravity and corruption of an entire species. Over thousands and thousands of Terran years, the ancient Aeldari, a race with souls of limitless passion and nearly limitless psychic capabilities, allowed themselves to be consumed with decadence. Because of their powers, passions, and unique connections to the Immaterium, the disturbances their depravity touched off were singularly dangerous.Even just this vague bit of knowledge is little more than rumour to most inhabitants of the galaxy. Still fewer are privy to the secrets that lie within the shrouded and nearly inaccessible vaults of the Black Library, the hidden craftworld that is the ancient repository of Aeldari knowledge located deep within the Webway. Within these sombre chambers, ancient manuscripts point to an unspeakable event that changed the galaxy forever. From the perverse thoughts, actions, and deeds of the Aeldari a new god was born, a very real god that was indeed a reflection of the species that unwittingly gave it life. Its violent birth signalled the eventual death of the species that gestated it.The tomes of the Black Library say that Slaanesh was born from the uncontrolled and excessive need for sensation that had come to preoccupy every moment of every day for nearly every Aeldari. Through the incredibly advanced technology and psychic mastery that the species had developed over the Terran millennia, they passed the days living in unimaginable luxury. They had no need to concern themselves with matters such as daily survival, manual labour, or warding off external threats. Nor did they feel bound by social constraints.They had no need to think of how their actions would affect others, not even within their own families, since there would never be a time when they needed anything from them. Everything was at all times theirs. Even death had no real meaning, for in that long ago time before Slaanesh's birth, the souls of the Aeldari possessed the ability to reincarnate from the Immaterium into newborn members of their species soon after death. There was as yet nothing within the Empyrean to hunger after those souls.The passions that burned deeply within the Aeldari's souls were unbound and freely explored to depths that other intelligent species could not fathom. A mind freed from all concerns of reciprocation, fear of reprisal, or death is able to turn fully inward and wander into unknown places, seeking previously unconsidered diversions and sensations. When an entire race unshackled its minds in this way, unusually powerful psychic energy was cast into the Warp, and the unnatural essences that reside in the Warp responded.The darkest moment of Aeldari history -- the Fall -- is chronicled as a cautionary tale, one that the keepers of the Black Library, known as the Black Council, study continually. Their hope is that some path toward a return to ascendance, or at least a way to avoid their species' ever-looming doom, can be found.The tale says that the vast majority of the members of the ancient Aeldari species, unprepared as they were for the god their unbridled passion and perversion had birthed, were consumed in an instant. Their minds, and worse their souls, were connected to Chaos in a way they could not have foreseen. They had become slaves to darkness, and when their newborn master hungered, the souls of the Aeldari were forfeit as its sustenance.