"Unknown Crusader's Diary" is an in-game book which appears in the Scarlet Enclave during the death knight starting quest chain. It appears after the creation of the Scarlet Onslaught and is visible in the phase after completing  .
The High General's fervor is ablaze in the peasantry! The Crusade's fleet grows mightier with each day and our ranks swell with able men. At our bow, a mighty sword sits poised to strike at Northrend and free us from this endless battle. Our stern is unsteady, though. With the Scarlet Bastion in flames, I cannot help smelling death on the wind at our backs.
Abbendis has lost her senses. She seeks to form a schism within the Crusade and attack the Lich King's very citadel with but a fraction of our most faithful! Does she mean to leave New Avalon and Tyr's Hand to burn as she sails over the edge of the world with our last defenders?
The morning is bright, pick and plow glinting as the men and women labor in the mines and fields. A shadow has come--a necropolis. This is not Naxxramas. The Scourge make camp nearby, and Abbendis has ordered that we fight to the last man. Have I sworn fealty only to cast myself beneath the juggernaut behind Abbendis' retreat?
The last page, the map, is a joke on how players used to do this (or still do) in order to reach Quel'Thalas, but end up swimming right through it and ending up at Tirifal Glades.