Brother Number One
From dieyoung
The mysterious figure known only as "Brother Number One" is referenced in multiple documents and conversations over the course of the game.
At this time, nothing is known about him other than he appears to have some kind of political influence abroad, based on the conversation with the farm in the Apricot Valley and seems to oversee events on the island.
There do appear to be multiple "brothers", alluding to some sort of cult or caste system, as there are references to Brother Number One found in documents written by Brother Number Two.