Dracorage

The Dracorage, also referred to as The Ravaging or The week of fury was a week long series of raids and attacks on humanoid settlements carried out by draconic races. It's events were the ignition for a half century long war across the realm known as The First War that led to the supposed extinction of the dragons.

Estimates of casualties differ greatly between scholars but the roughly agreed upon number lies between 200,000 - 500,000 lives lost during the period that can be directly attributed to the events, including deaths after this period as a result of illness, poverty or injuries the death toll climbs past 1,000,000.

The Dracorage was later revealed to have been caused by a power spell cast by the elves now known as The Dracorage Mythal looking to unite the other races against the dragons in war.

Background
Decades of skirmishes, clashes and confrontations between the overlapping Elven Kingdoms and Draconic territory contributed to growing tensions between the two races for years prior to the First War. A number of summits were called to try and placate the warring factions to no avail, the most notable being the Highpeak meeting that ended with the deaths of one Dragon ambassador and 2 Elven dignitaries. Over time the Elves tried to muster support to go to official war with the dragons to end the ongoing feud which only garnered the backing of the Dwarves who were already enemies of the dragons as known from the regular Dragonmoots. With dwindling support the Elves devised the dracorage to unite all of the allies under one banner to fight against the Dragons.

The Dracorage Mythal
A group of Elves known as the Mystic Coucil, advisors to monarchy of the Elves skilled in magic and divining congregated in secret and devised a plan with the King's permission to act as the trigger for a united war. The outcome of 3 years of planning was a powerful mythal that was to be cast upon the Kingslayer star that appears once every 5 years. The spell was designed to incite mindless fury amongst all races that harbored Draconic Blood which as a result also affected half blood dragon races like the Dragonborn.