Vampires are a type of monster mentioned in Jekyll and Hyde. While Roger Bulstrode thought there were vampires attacking innocent victims, this turned out to be the work of Olalla Jekyll and her use of the Sangría Maxilla - which leaves similar 'bite' marks on its victims to those one would expect from a vampire. No true vampires have been seen in the series thus far, and it is unclear whether the MIO have actually encountered them in the past, or Bulstrode was merely making an assumption.