The metreon cascade was a weapon of mass destruction conceived by Dr. Ma'Bor Jetrel of the Haakonian Order, and then built by a team of scientists lead by him. However, Jetrel downplayed his role, calling the weapon a scientific inevitability that would have been discovered by someone else if not by him.
It used unstable metreon isotopes to create a devastating explosion. The resulting radiation poisoning killed those who were not destroyed by the initial blast. Jetrel claimed that this poisoning was unforseen. Furthermore, sufficient exposure to metreons resulted in the deadly disease metremia.
The flash was visible from nearby Talax, where observers subsequently lost sight of Rinax due to the metreon cloud enveloping the moon. As of 2371, this cloud still persisted. More than a quarter of a million people were vaporized, and thousands of others eaten away by Metreon poisoning. Over all, more then 300,000 people died. The aftermath was described as such:
- "hundreds of fires, and there's nothing there – just smoldering ruins and the stench of seared flesh. But in the distance, in the middle of all that emptiness, from out of this huge cloud of billowing dust, he can see bodies moving, whimpering, coming toward him. They're monsters – their flesh horribly charred, the color of shale."