Type-V mutant is a term used in the Battle Angel Alita: Last Order manga to refer to humans who are infected with a retrovirus called the V-virus. The virus causes mutations in the DNA which result in the carriers exhibiting vampire-like characteristics, most notably pronounced canines and a thirst for blood. The origins of the V-virus have not been made clear, but Type-V mutants have existed throughout human history. Only in the late 20th century did advances in biology reveal that vampires were once humans who had been infected with the V-virus.