The Bleed is the anti-matter that fills the space between the realities of the Multiverse, separating them. The Monitors can weaponize and use the Bleed for their own advantage as there is a special breed of them called the Weavers, who have been trained since birth to manifest it as a weapon. They use it to end all existence so they can maintain order. They have also reprogrammed some Manhunters, who are running on Bleed, to deal with the "supers" and "metas" of each Earth.