The Bloodstorm

A hundred thousand leeches, mosquitos, and parasites form a roiling mass of hunger and malice. It moves like a storm through the tunnels and caverns of the Emperor's Peak, constantly in search of its next meal. Though it has many bodies, it has just one, startlingly clever mind. The flames and smoke of the cities keeps it at bay, but in the darkness, it is at home. The dwarves of Highhelm have learned how to live with the threat, but those traveling deeper into the mountain must always remain vigilant.

In the swamps of the Tanglebriar, food is difficult to come by. So when a grievously wounded demon, a shemhazian known as Gratheyr, fled into its waters to escape from his enemies, every starving creature swarmed at the smell of blood. As the creatures devoured his flesh, they were corrupted by his Abyssal blood, and their hunger only grew. They feasted until nothing but his heart remained, still beating at the center of the swarm, binding it to a single will. With its meal finished, the bloated swarm left the swamp in search of its next prey. It moved aimlessly, hunting animals and travelers alike, until a great rumble beneath the earth attracted its attention. The Bloodstorm followed the vibrations deep underground, toward the scent of sweat and the sounds of voices.