I know there ARE drop rates, but I'm beginning to think that it's a chance one will drop after a FATE is completed successfully and is awarded to a party that gets a Gold rating...and then one person gets that atma. I also think the percentage goes up as the level of the FATE goes up. I got 5 today - 3 of which I got at lv40+ FATES, 4 of which I got while FATEing solo in between dungeons. The one I got in a party took forever. The ones I did solo took significantly less time. The ones I did in lesser populated areas happened a lot quicker too. I spent a good bit of time in the Central Shroud in a party with no luck, but did two FATES solo in North Shroud and got it.