The giant vampire bat is a variety of the desmodontinae subfamily of bats and is quite distinct from its siblings. It is around 30% larger than the average common vampire bat with a wingspan that rivals that of some birds of prey. The vampire is actually no different to the common vampire bat due to genetic mutation, they both share a common ancestor as both species engage in sanguivorous habits, it is likely they only evolved once, as did all vampire bats.
In the United States, Giant Vampire Bats or Shiftdevils are mutated vampire bats. Shiftdevils often hide in dark caves and mines, only revealing themselves outside during the night to ambush their prey. They swoop down and grab onto their target, digging their sharp, needle-like wings deep into the skin as they feast on the outer skin until the animal either kicks them off or collapses.
Their groupings can consist of hundreds, with the main roost revolving around an "Alpha Male". Nomad bats will often be taken in younger bats and nurture them, allowing them to spread their seed.
It is generally believed that the Giant Vampire Bat may be the most common species of bat due to the death of plant life following the Great War, which leads to the growth and survival of this species.