Werekin are a particularly brutal breed of shape-shifting monster which take the form of various predatory animals, albeit a humanoid beast version. They are often described as being more dangerous than even Vampires due to their similar levels of resilience and superior strength.
Werewolves
Also called Wolfmen or Lycans, Werewolves (人狼, Jinrō) are the most well-known form of werekin. A supernatural creature that transforms from a human into a humanoid wolf-monster under a full moon. Like vampires, werewolves are vulnerable to silver or silver colored items. When the sun rises, they revert into their human form with no memory of what happened.
History
Before the days of Hellsing or even The Dawn, Werewolves were plentiful. In The Dawn, when he and a teenage Walter face off against The Captain, Alucard recognizes what he is immediately, indicating he's run into their kind before. Given the Hellsing Organisation's mission and purpose, it is possible that they were fully or partially responsible for the near extinction of Werewolf-kind. However, given at the time, Arthur Hellsing was still the head of Hellsing, meaning that Abraham Van Helsing could've probably be the one who has ran into them and killed their kind with his group. In other side, it is also completely reasonable to assume that Alucard was the one who've slayed their kind too.
Alucard remarks he thought their species had been defeated, implying that The Captain is the last of his kind.
Abilities
In general, Werewolves appear to be stronger than Vampires. What they can naturally do and not is unclear, as it is possible the Doctor tampered with The Captain's biology, making him modified like Alucard.
- Superhuman Strength: Werewolves are several times stronger than average humans, able to lift large objects that normal humans could not and inflict incredible damage with physical attacks.
- Regeneration: The Captain is seen to lose part of his left arm during his fight with Young Walter in The Dawn, so it is reasonable to assume werewolves can heal major wounds like a vampire can. It is also clear that the healing process is not as fast, since The Captain lost both his arms during his fight with Seras and did not grow them back immediately.
- Thick Skin: With its thick skin, werewolves are some times more durable than that of even the strongest vampires, with the Captain being able to pull Walter C. Dornez's Monofilament Wires, which was later shown being able to slice Alucard himself in half.
- Transformation: Werewolves are generally more agile than vampires, so it can be easily assumed that the werewolves are able to do this. In folklores and legends, these werewolves can only transform when the light of the full moon strikes them; furthermore, when they revert back to normal - specifically, when the sun rises once again: they have no memory of what had happened during their time as a werewolf. However, the Captain can turn into a werewolf completely at will - even he can turn part of his body into a part-werewolf; which basically means that he can turn his head into a werewolf while having a man's body, much like how Alucard can turn his head into a baskerville while keeping his human body intact.
Weaknesses
The only known weakness werewolves have is anything silver-related, including bullets and teeth.