The Bleed is not a universe in itself, but it is defined as the space between parallel universes.
Many with the ability can travel between parallel universes through the Bleed, or, simply, an arterial duct connecting to universes. Traveling through the Bleed is not without danger though and sometimes objects or beings get lost, appearing in times and places they were never meant to go. In addition, the Bleed has mutagenic properties that alter the make-up of any sentient being that enters it directly. The effects can be beneficial or detrimental, depending on the circumstances of the exposure.