Neither Abram nor Edein are really "neutral"; they just have bigger fish to fry. Oculus is this game's Assassin sect, only without the indoctrination, and the Institute are just another BioCorp splinter group, focusing on isolationism and eugenics instead of expansionism and assimilation. They are all in some way involved. The Drones may be little more than bandits, but if anything, they are more genuinely neutral than anyone else. Of course very little is known about their actions in North Underrail, which should probably be far more representative of their actual movement.