Gammageddon killed 99.9% of the population, leaving 2,000,000 alive globally, compared to the estimated 2 Billion. The ozone was severely diminished, the whole system was affected. However, due to dumb lucky chance, the 0.1% did survive. The next years were to re-build and attempt to survive once more. This is not one of the worst possible events that could have hit, but it is one of the worst. Due to the GRB's Position in the sky, mostly those outside of the old world were affected. this meant massive deaths in the new world, and some polar regions, regardless of area. Places like northern parts of the UAPF, and north NME got directly shot, killing countless. due to large parts of the east continent's goverment being wiped out, civil war began in the power vacuum. multiple new states formed, but never as large as they were united, and never as strong. Those in the equatorial regions began building up, and formed from the ashes left in the wake. Countries reformed, and progress carried on. those 1.998 Billion who died were never forgotten, ever onto the distant future.
Gammageddon was majorly caused by Drama between individuals. Two neutron stars collided via admin events, and off the grb went.