The Week of Nightmares or Week of Nightmare (most likely Monday, June 28 to Sunday, July 4, 1999) is the name given by vampires to the week in which Zapathasura, Antediluvian of the Ravnos clan, awakened. This is generally seen as the beginning of the Final Nights, the time of signs and portents leading to Gehenna.
When Zapathasura awoke in the Ravnos homeland of India, it devoured all its nearby childer in moments, and sent psychic ripples across the world and spirit realms. Psychics, madmen, and anyone even vaguely touched by the supernatural felt on edge or suffered visions and nightmares. The nightmares usually featured the Demon-King Ravana (representing Zapathasura).
A vaguely human figure staggered toward Tieh Ju through the rain. She guessed it might be male but could not be sure. Flakes of black ash covered the remains of its naked, shriveled body. One arm hung as a stump of tattered meat. Hallucinations of pain radiated from it, like the vibrating, inner light of migraine. It had survived the wrath of three Bodhisattvas and a bath of nuclear fire. Tieh Ju knew that, even weakened as it was, she could not fight it. If she tried, it would replenish its strength on her chi. Although the thing had no eyes, only sockets oozing black blood, it turned to face the pair. Its fanged jaws worked, and it rasped out, "Blood. Feed. Hunger." It spoke Sanskrit, the ancient tongue of India.Time of Thin Blood (appendix)
Zapathasura rampaged across India to Bangladesh for two days, calling its childer to it, but on the third day was attacked by three of the eldest Kuei-jin Bodhisattvas. All this supernatural activity did not go unnoticed by the forces of the Technocracy, who used orbital mirrors to focus the power of the sun on the Antediluvian, but the Boddhisatvas and their allies had called a supernatural storm to shield themselves from sunlight while they battled the Antediluvian. The Technocracy then employed magical "neutron bombs", killing all of Zapathasura's combatants – including those who were controlling the storm. As the clouds parted, Zapathasura had been weakened enough by the bombs and battle that the focused sunlight destroyed it.
The awakening of the Antediluvian had a profound effect on all its childer. While the battle raged, Ravnos vampires' power over Chimerstry grew stronger, though harder to control. But at the instant Zapathasura died every Ravnos on Earth felt an uncontrollable bloodlust, compelled to destroy or diablerize other members of their clan. This madness lasted for four days, and only a small number of Ravnos still survive, mostly of higher generation.
The events of the Week of Nightmares were covered up by all parties involved, ascribed to a combination of an out-of-season typhoon and a mid-level military altercation between India and Bangladesh. A swath of territory stretching from Calcutta to Dhaka was almost entirely depopulated. The Gauntlet effective vanished for a time, and remained unusually thin long afterward. Destructive Umbral storms and rage-filled ghosts and spirits plagued the region, though these abated over the course of several months.
Other apocalyptic events also occurred during the Week of Nightmare, though not all of them are directly related to Zapathasura's awakening.
- A Red Star visible only to supernatural creatures appeared in the sky. It is known as Anthelios, or the "Eye of the Wyrm", to the Garou, who see it as a sign of the Apocalypse. Kindred come to call it Wormwood and see it as another sign of Gehenna. The Kithain know it as the Eye of Balor, and mages dub it Telos. Those with advanced supernatural senses (Auspex of at least level 2, for example) see it as brighter than Venus, surrounded with a halo like a comet. All who are able to see it know instinctively that it is evil.
- A pup, the fabled Perfect Metis, was born on the last day of the Week of Nightmares to two Metis Garou.
- The Avatar Storm began in the Umbra.
- It has been suggested that the Technocracy's bombs, capable of disrupting the spirit worlds, contributed to the instability of the Tempest, and therefore the Sixth Great Maelstrom later that year.
- Zapatharusa's death blasted open long-sealed trods in the Dreaming, releasing the Denizens, the Adhene, to once more walk the Autumn world. The Naraka, an Adhene that made their home in the Dreaming around Bangladesh, were transformed utterly by the cataclysm, reborn as embodiments of destruction, with all memory of what they had once been lost to them.
- It is also suggested that the Technocracy's bombs were directly responsible for opening the cracks in the Abyssal prison crafted to hold Fallen Angels, and thus began the events detailed in Demon: The Fallen.
- In the Apocalypse sourcebook, the "Last Battleground" scenario suggests that following the Week of Nightmares there is no longer any Umbra where the "spirit nukes" went off, suggesting the level of devastation from the weapons was catastrophic. This scenario, like most of the book, is optional and not intended to be canon.
Although the first reference to this event (in Time of Thin Blood) consistently calls it the "Week of Nightmare", all subsequent references name it as the "Week of Nightmares".
Kindred debate when exactly the Week of Nightmares fell, with some claiming it landed just prior to the turn of the millennium, while others conflate it with the supposed commencement of Gehenna. In truth, the “Week” of Nightmares sprawled across years, sweeping up several thousand vampires in its wave. During the Week, an impossibly ancient vampire arose and purged its own clan: the Ravnos. Thin-blooded vampires emerged with omens and portents as the Red Star, Anthelios, blazed in the night sky. The Ravnos Antediluvian met Final Death in July 1999 at the hands of parties unknown, armed with advanced weaponry and the power of the sun. Before he died, he drained vitae from all his clan, driving them to frenzy and cannibalism in his death throes. Thick, sentient ropes of his vitae stained the ground in Bangladesh where he fell. The noonday sun did not destroy it all and some can own a small vial containing the Blood of the Ravnos Antediluvian. 
- , p. 395