For anyone unfamiliar with what Space Wolves represent (or are unsure of what they even are) they are a fairly well known legion of space marines from the Warhammer 40,000 universe. If you are still unsure of what that is, you probably just need your memory jogged. Warhammer is a tabletop game that utilizes painted miniatures to represent players in the vast Warhammer world. Warhammer 40,000 takes place 40,000 years after the high fantasy based original Warhammer. Space marines are considered the ultimate warriors.
In this regard, consider Space Wolves a legion of space marines that are not really keen on following anyone else’s rules but their own. Space Wolves are regarded as the bad good guys as they are not tainted by the forces of Chaos and they do still fight for what they believe is right. Although they are not prone to Chaos infused mutations in the traditional sense – mainly because the chaos Gods are not responsible for the mutation directly – they still mutate. Under heavy stress in battle some may mutate into a werewolf like form. In this form they are highly resistant to the powers of chaos. It requires exposure to a large dosage of the power of Chaos in order for them to mutate.
The Space Wolves army is one of the most powerful space marine legions because of their high resistance to cowardice. They are brave and will very often fight to the last man rather than retreat. In order for regular Fenris warriors to become a member of this legion it requires them to show tremendous heroism or even death while in battle. After this they are then put into a platoon like structure known as a Claw. They have to go through intense physical training and complete almost impossible missions before being able to take the Canis Helix and multiple tests to find if they are able to become true Space Wolves.