TheTrueSorrowMaker's board-to-board with Didactic Mind
From Destinypedia, the Destiny wiki
There is a mention to the events of Preservation in Rhulk's Legacy section.
I would hold off on labeling the whole House of Dusk working for the Shadow Legion since the fact they barely function as a unified group and more of two separate crews under the same banner but operating between different leaderships.
Stop with the private messaging.
It doesn’t say that he wrote the 7th Book, what he wrote were etchings from the Book that existed long before, it even says that it is ancient Hive text which would mean that he didn’t write them.
They were added so that subgroups (i.e. Shadows of Calus, Disciples of the Witness, Silent Fang, City Factions, etc.) were indicated their loyalties they are in greater parties. ([[Loyalists, The Dread, House of Wolves, The Consensus.
Also Darkness-affiliated minds like the Scorn, Taken, and even the Nightmares must serve something greater; either a master, creator or progenitor who has had a major role in the story or lore involved in their creation or control.