From the Kickstarter Page:
With this expansion, Forbidden Lands gets a whole lot weirder! The Bloodmarch is the name given to the volcanic region west of Ravenland, now accessible as the Shadowgate Pass is again opened. This ancient place of battle-ready horse riders and secretive dwarves is rapidly changing due to the demonic vegetation spreading across the land. Most see this red curse as a threat to all that is good, while others view it as a good thing – or at least a necessary evil needed to reach other goals.
The PCs can choose a side, or side with themselves, as the Legacy of Horn campaign sets the PCs on a hunt for Horn´s Astra, a legendary set of artifacts sought by many in the ashen land. These powerful items are said to be able to stop the demonic growth, or be powerful enough to ensure its triumph.
Similarly to the The Bitter Reach, The Bloodmarch expands the game world with a complete new area, directly west of Ravenland depicted in the core set. The map of The Bloodmarch, designed by Tobias Tranell, is divided into different terrain types, and uses an hexagonal grid to regulate movement. Just like in the core game, players can go anywhere they like on the map and explore the world the way they want. Due to the modular way the campaign is built using adventure sites, the GM can make sure the players don't miss the story without any need for leading them by the nose.