I am looking for a word that describes an event which marks the beginning of an apocalypse or era of darkness. It shouldn't describe the aftermath itself, but rather the instigating moment.
However, I'm looking for contextual suggestions, so a little background might be appropriate. The word is meant to describe the reopening of a gate/barrier or the breaking of a seal, which was closed long ago. This reopening portends terrible times.
So far, I've thought of calling it "the Fracture", but I'm hoping to use that term for something else in the story, so alternative suggestions are welcome. Words like calamity, cataclysm etc. won't work, because they don't actually describe the specific event which I mentioned above.
Sample Sentence 01: "The Fracture has led to thousands fleeing south to escape the devastation."
Sample Sentence 02" "I was born after the Fracture, but I've heard enough stories to appreciate what little I have today. For others, it was much worse."