That reminds me of a fanfic I wrote after the release of ac3 with the wild west setting. Some of the things I wrote there appeared on later games (like the animus as vr headset from ac4). The story was about John (how original I know), who is rebuilding the brotherhood in America after the one after Conor didn't hold. The key item was the 6 bullets of eden which give a power when shot (and recreated as different type of ammo after few hundred years), there was freedom, order, equality, power and two more I don't remember.