Scout's Blood is the result of the task "Scouting the Commonlands"
You get this task from Thanuel Mergon in Bloody Kithicor by hailing him saying assume then plight and scout to get task.
The steps of the task are as follows...
Speak with Supplymaster Kibrek (He is in the same camp as Thanuel Mergon)
Explore Dallik's Blackhearts warcamp (first camp you cross in the old commonlands)
Explore Nightblade Halberdiers warcamp (2nd camp in old commonlands)
Explore Painstorm warcamp (3rd camp in old commonlands up in the sand)
Explore refugee camp in the Commonlands tunnel
Speak with Sil Silverstar (In the tunnel)
Speak with Tallyd Gorenault (in the tunnel)
Speak with Merrin Beanslinger (in the tunnel)
Speak with Diennic Lightheart (back to same camp as Thanuel in Bloody Kith)
Speak with Thanuel Mergon (to complete the task)
will update with full text when I get complete the log in game.