The Vampire Bats escaped with the Giant Rats from a military research laboratory where they were being evaluated for use as weapons and soldiers.

They were the second batch to escape the facility months after the Red Bat Gang.

After the first skirmish with Gore Paw and his crew in London, they retreated to set up a nest in London’s sewers. It was down to Gore Paw and the Gang to find them and return them to the laboratory.

Those that escaped regrouped and fled with the Were Mice to other countries.