16th of Halsimos, 638 YSE
(or, how 3rd Edition D&D rules entered the campaign)
It is a perfect day of late summer as you go about your day's business. Then suddenly, a sound, a moment, a shift, the oddest of sensations, as if something that you could hear with your tongue, or smell with your ears has happened. Then the perfect sky is marred by a bruise that begins to appear in the west. It grows, darkening and... stretching? It twists and writhes, then develops into a tear of sorts, akin to a vast, puckered scar. Within it appears darting, persistent lightning; there is a felt, rather than heard, crash of sub-sonic thunder. Then it explodes with a sound and shockwave that drives you to your knees. Shards of realities, like two-dimensional facets of crystal, fall from the sky. Within each shard you can glimpse the image of some different reality, like windows holding the memory of some vista they once looked out upon. Some shards land nearby, just beyond the hills. Other vanish over the horizon.
From out of the rift above, a Manifestation appears, a massive figure, a sylph-winged humanoid form somewhat crystalline, somewhat gelatinous in appearance. It is transparent and translucent. It rolls across the sky, above the clouds, then “stands” and assumes a defensive posture. A second figure, like, and unlike, boiling gray-white mud, follows the first through the rift. The first waves its gargantuan arm, whence spring shimmering ripples that fan out across the sky. The second responds defensively, deflecting the shimmering wave back to the first figure. The wave hits it, and it rolls groundward. Its wing brushes over, through the ground. As the wing-wave passes along, you see colors beyond it shift subtly, becoming somehow richer. It continues along, rushes upon you, blasts past you. You feel caught up, as if in a windstorm, though this not a storm of moving air, but a storm of shifting reality.
The Manifestations, which some might call gods, continue their combat, sending off more waves, bolts, and bubbles of alternegy. There are other shifts of color and material as these spread across the land in waves of colored and white un-fire. The figures in the sky continue to trade waves and bolts, until finally, the second opens a rift and dashes through it, off to some other Prime. The first figure follows it. The silence of normality settles across the land. But that land is now subtly different. Deep inside, you feel somehow that the nature of your reality has fundamentally changed.