Night of Terrors
In the fifth month of 3654 BBY, a dark side tremor rippled through the entire galaxy, anyone with Force Sensitivity was suddenly enveloped in dark side energy for mere moments but it was a terrifying and traumatic experience as they were exposed to their darkest fears, impulses, and inclinations for an eternity of seconds.
On Ziost it was early in the evening when it struck, on Coruscant it was the dea of night, while on Bankor it was mid afternoon, but all felt a cold wave of dread and power ripping through their bodies. The Jedi called it the Incident, while the more dramatic called it the Night of Dark Nightmares as their dreams were troubled by imagery of worlds turned to gray ashen wastes and all life eradicated. The Sith called it the Night of Terrors and although more accustomed to the Dark Side were still confronted by horrific images of their failings, their weaknesses, and their enemies all rising against them.
The physical effects were minimal though the young and the frail found blood seeping from their eyes and mouth from the pain or were even driven to catatonic states unable to deal with the influx of dark side energy. For weeks afterwards Force Users were troubled by nightmares and paranoia, it subsided but all force Users remember where they were when the Night of Terrors struck, it was a profound and traumatic experience that exposed how small and powerless they truly were.
The source of this tremor is believed to have emanated from Sith space, but even that is just best Jedi conjecture as scientific study into such Force effects is minimal at best. Those that have felt the presence of the Sith Emperor even claim that it was the dark Lord rising from his deep slumber that caused the ripple. Many Sith scoff at such superstition and believe the source was a more natural but powerful occurrence, perhaps a cosmic event that destroyed billions of lives on some uncharted world.
Game Mechanics: Every Force die roll generates an extra dark pip that can be used as normal but costs 1 strain on top of any other normal strain for using Dark Side pips if a light side user as well. The player must have a Force rating of 1 or higher to benefit from this as this modifies the Force die roll.
There may be other unknown effects of utilizing this background dark side energy.