1883 eruption of Krakatoa

The 1883 eruption of Krakatoa, also known as the youkai detonation of Krakatoa, Black Krakatoa, Incident Fireball, and the 1883 Krakatoa Disaster, in the Sunda Strait begun on the afternoon of Sunday, 26 August 1883 and peaked on the morning of Monday, 27 August 1883, when over 70% of the island of Krakatoa and its archipelago were destroyed and collapsed into a caldera.
The eruption resulted from International Fairy Offensive Order No. 29, an international fairy military campaign intended to destroy Malice, Urusumba, Yurulumna, and several other demigod-tier spirits and their armies gathering and stationed in and around the Krakatoa archipelago. Due to blatant ignorance of thaumatological symbols resulting from the arrogance and carelessness of the predominantly powerful fairy factions, little reconnaissance, mobilization of roughly 30% of the entire world's fairy factions, lack of research into anomalous-integrated technology and lack of investigations into captured hostile youkais and of thaumaturgy/thaumatology to properly contain Krakatoa, International Fairy Offensive Order No. 29 became not only the longest and hard-fought campaign but also a catastrophic fairy military disaster which brought unintended and preventable consequences; despite this, humanity who learned of Krakatoa's eruption thought of it as an event of immense proportions caused by mundane seismic activity.
The eruption became one of the most deadliest and most destructive volcanic effects in history and explosions were violent which they can be heard from no more than 3,000 miles away, leaving 40,000+ people dead. The eruption also became a catastrophic disaster for the myriad fairy factions, especially the more predominantly powerful factions, for not only it caused unintended geographical and global climate effects but also severely wiped out twenty million fairy military personnel (among those were the fairy forces' best soldiers), a fairy armada of thirteen fleets and three hundred youkais that gathered and fought there and cause discord among the myriad fairy factions which led to an occult cold war between the powerful fairy factions. The destruction of the fairy forces present there also gave a respite for hostile spirits to attack fairy-controlled areas.
The event, however, also brought several positive consequences. Years after the event and five months before the Southern Novayan Revolutionary War of 1889-1891, the disparate and myriad Novayan fairy factions merged their factions and occult divisions into a single faction and pooled its resources into investigations, research and development of anomalous-integrated technology (soon to be widely and commonly accepted as and called paratechnology), adopted a careful and cautious mindset and thaumaturgy, and fought against the predominantly powerful fairy factions, especially the Hispanian fairy factions, that were not only defeated by the Novayan fairies but the Hispanian fairies' defeat disrupted the fairy status quo and the end of the fairy occult cold war. The Novayan fairies' rise to power resulted from studies and investigations into the cause of the failure of International Fairy Offensive Order No. 26.
Another positive outcome of the Krakatoa eruption also saw the change in the status quo of the Fairy-Spirit Wars and the fairies' doctrines of combating the spirits. After the catastrophic failure of International Fairy Offensive Order No. 26 and the rise of the Novayan fairies, the frustrated and defeated powerful fairy factions (the old guard fairy factions) directed their efforts into investigating their campaign's failures and errors. After the end of their investigations - which revealed similar scenarios (with the difference being the scale, magnitude and close-call of said scenarios) and the problems and errors which preceded them - the old guard fairy factions, in collaboration and conjunction with the new generation of fairy factions, modified or discarded their spirit containment protocols and doctrine that led to the creation of the Secure Contain Protect Initiative, a vastly-made answer to not only counteract the more hostile spirits but also prevent similar outcomes (referred to as Krakatoa-class events) by secure and containing the more hostile spirits wherever they are found and protect fairykind, humankind and the more benign spirits.
In spite of this, the fairy factions marked the event as Black Krakatoa in commemoration of the fairies who lost their lives in the battle of Krakatoa and the eruption.