Legend has it that William Colvis Yunus was bitten by a wolf, infected with rabies virus and became the ancestor of a werewolf. As for the true origin of the werewolf legend, it is still difficult to trace it back, with different opinions and a lack of recognized origin.

Legend has it that around 400~500 AD, somewhere in Europe, a plague occurred in the village where Alexander Colvis Yunus lived, and people in the village died one after another. Only Corvinus survived, but he had a genetic mutation that could turn the virus into his own place and never die. His son also inherited this feature. Alexander's son Marcus Colvis Yunus was bitten by a bat, infected with bat virus and became the ancestor of vampires. Another son, William Colvis Yunus (bitten by a wolf, infected with rabies virus, became the ancestor of a werewolf. Marcus and William inherited Alexander's diluted blood and turned their characteristics into a special infectious disease. People bitten by Marcus will become the same vampires, while those bitten by William will become werewolves. Since then, vampires and werewolves began to wreak havoc in Europe and spread all over the world. Alexander, the same ancestor of vampires and werewolves, left two mutated sons, who have been paying attention to the development and survival of these two races in the dark for hundreds of years.