The Mi-Go Infiltration of 95 CR was one of several key events leading the end of the realm and the destruction of Quelmar at the hands of The Tourbillion.
Background
As the CR era progressed, and the vortex at the center of the realm slowly tugged at the roots of the realm's landmasses, there were several calls to action. It was believed that with enough proactive support from nations around the realm, foundations and construction could be created to counteract the pull of the Tourbillion.
One group that supported these experimental solutions to "tidal change" were the Southern United Nations, a geopolitcal entity that encompassed most of the nations now residing in Amusa. 95 CR was a critical point in the tidal change timeline, and swift action needed to be agreed upon.
The Opposition
Eldritch creatures from beyond the stars, known as the Mi-Go, operated under strict orders to sew chaos and destruction in the realm. To them, tricking Quelmar into destroying itself was the ultimate sacrifice they could make to their great old god Nyarlathotep (or Nygo for short).
The plan was simple, during the SUN conference of 95 CR, where tidal change was a key issue, the shapeshifting Mi-Go would disguise themselves as fellow politicians and other notable figureheads. While in conference, their goal was not to assist in the talks, or to commit acts of violence that might otherwise unite the nations against the Mi-Go, but rather insert any snarky, snide, or back-handed remarks into the conversation that would slowly but surely raise the ire of the nations against each other.
As a result, when talks boiled, so did tensions, and while the nations did their best to cement a plan of action against the Tourbillion, the framework fell apart.
Result
For the next century, conferences and talks would be tainted by the remarks made by delegates at the SUN Conference of 95, and future attempts to stop the Tourbillion failed. Ultimately, time would heal the wounds, and the nations would put the words of generations' past behind them, only to discover it was too late for any action to be taken, the pull of the current was too strong, and the tides had turned. Quelmar was doomed.