Disciples of Osiris is a Grimoire card from the original Destiny (Destiny 1), found under Allies → Osiris. Grimoire cards held most of the game's lore and were read on Bungie.net and in the companion app, not in the game itself.
Card text
ENCRYPED: Champollion Algorithm v.4
KEY: ############################VANC
My brother,
Despite all of Shaxx's work with the Crucible, we must accept that the Tower may never be ready to accept the Trials. But, as many Guardians flock to the Reef, we are suddenly presented with not one opportunity, but two.
Go to the Reef. Tell Guardians your story. Give passage to any Guardian that requests it. If the Tower learns of this, do not fear. If they know of the Trials, the Tower will not suspect your other motive for dwelling so close to the margins between Light and Dark.
Your sister,
Faora
KEY: ############################VANC
My brother,
Despite all of Shaxx's work with the Crucible, we must accept that the Tower may never be ready to accept the Trials. But, as many Guardians flock to the Reef, we are suddenly presented with not one opportunity, but two.
Go to the Reef. Tell Guardians your story. Give passage to any Guardian that requests it. If the Tower learns of this, do not fear. If they know of the Trials, the Tower will not suspect your other motive for dwelling so close to the margins between Light and Dark.
Your sister,
Faora
Grimoire text written by Bungie, shown as it appears in the Destiny 1 game files.