Book of the Shadowlands (1e)
Discover the odious realm of the Dark God¸ Fu Leng. Corrupted by his twisted evil¸ spawned with the desire to wipe out humanity from the face of Rokugan¸ the Shadowlands crawl with unspeakable monstrosities and a blight that can transform the bravest man into a gibbering fiend.
This one is written by a well known crab by the name of Kuni Mukona as a document with his research on the mystic Shadowlands and it's dangers¸ and of course with the game info put on the sidebars.