The Lone Wolf names of Roost and Ryker
If you encounter an abandoned shack in the Meadows, you can find a secret export ledger wedged between the wall and a dresser. This tome does not appear on the map unless you are standing in the wheatfield directly outside the shack, otherwise it can only be highlighted if you hover over it with your cursor.
The tome is a ledger containing the pseudonyms of three clients: Grizzled Whisper, Dusty Rogue, and Bleeding Baron.
At first glance, the only useful information appears to be on the second page. The ledger tells us the Bleeding Baron's shipment was delivered behind the woodpile, but never retrieved, allowing the player to dig up a bag of loot.
If the player visits the drop-off locations of the other two clients, i.e. Dusty Rogue, no loot may be collected because the shipments have already been retrieved.
But this tome is actually connected to the side quest, The Merchant: the second page provides context to the fate of the travelling merchant, Baran Levere, while the first page hints at the codenames of two prominent Lone Wolves not otherwise revealed in the story.
Ifan ben-Mezd, the Silver Claw, explains that all those who are successfully initiated into their ranks are assigned a codename in the form of a two-word moniker.
Codenames are necessary for Lone Wolves who hold active contracts to protect their true identities — they reduce the risk of exposure or retaliation if communications are intercepted, and prevent any transactions from being traced back to their origin. Arranging drop-off locations would allow supplies to be delivered discreetly, minimizing the need for direct contact between the operative and the courier, hence the secret ledger.
The implication of the ledger is that it once belonged to Baran Levere, a merchant in charge of delivering the shipments to drop-off locations specified by his clients. At least -- until he is assassinated, his entire inventory stolen, and his identity assumed by the Lone Wolf, Callo.
Clearly, the Bleeding Baron is a morbid play-on-words for Baran's bloody death, suggesting that Callo is the Bleeding Baron mentioned in the ledger. It is implied through storyline dialogue that Callo requested the shipment so he could lure his target to a more discrete location — the abandoned shack — and kill him.
In Act 2, Ifan gives the player a test to determine what their Lone Wolf name would be. He admits that he doesn't remember all of the questions, but Dusty is one of the answers, implying that the Dusty Rogue in the ledger is a Lone Wolf operative.
From the ledger, we know Stonegarden is Dusty Rogue’s specified drop-off location. Since Ryker is one of the only living beings in the Stonegarden — and a confirmed Lone Wolf — he is almost certainly Dusty Rogue.
Keeping in mind the Lone Wolf naming scheme, now that we’ve identified two-thirds of the clients in the tome are Lone Wolves, it becomes even more apparent that the ledger’s purpose is to keep a record of Lone Wolf exports, in particular. So, we can safely assume Grizzled Whisper must be the cover identity of a Lone Wolf operative, too.
If you visit the Cullwoods Mill, the Lone Wolf camp, you will notice every assassin is named with two-word monikers (i.e. Mummie Dearest, Slumberjack, Elixir Mixer, Honeyhook, etc.) -- everyone except Roost Anlon.
Since Callo is Bleeding Baron, Ryker is Dusty Rogue, and the names of all other Lone Wolves on Reaper’s Coast are known, by simple process of elimination, Grizzled Whisper must be Roost.
