Powers and Abilities
In the Underworld films, Lycans display a number of greatly enhanced physical attributes. As with their rivals the vampires, Lycans are immortal, able to live for hundreds of years (William survived over 800 years of captivity with no food or water in hibernation). They possess enhanced (superior even to those of wolves, not just humans) senses of smell, hearing and sight and are also able to sense vampires in close proximity to themselves and possess physical strength, durability, reflexes, and speed superior to those of vampires, and have been seen to power through solid concrete walls in Lycan form. It should be noted that in wolf form Lycans seem to be far stronger than the vampires, as every hand-to-hand confrontation between the two races under normal circumstances has ended with a Lycan victory with the exception of elder vampires like Viktor. A first-generation Lycan was able to send a fully armoured vampire flying at least ten feet through the wall of a villager's hut. These traits seem to apply even when the Lycans are in human form, as Lucian was seen to be able to catch a moving car, and subsequently survive being hit by it at point blank range with no injuries. Lycans can also use their claws and strength to scale sheer surfaces, having been seen to crawl along walls at great speed in pursuit of prey.
Lycans also possess superb physical resilience and remarkable regenerative abilities: both Lucian and Raze are wounded, by silver bullets and Selene's throwing stars respectively, yet they bear no marks or scars when they reappear later in the film. Their recovery abilities are hampered by the presence of silver in their bodies. However, to older Lycans, the silver is rarely fatal. Lucian displayed the ability to force Selene's silver bullets out of his body through muscle strength, although it is mentioned in the first film that the silver is fatal if it penetrates the internal organs. They possess heightened senses (which allow for them to detect the presence of vampires), and the ability to land on their feet, like cats do, as seen with Lucian, after being hit by Selene with her car; and Michael, after leaping out of the window of the Death Dealer safe house from several stories high, Michael landed on his back several times, suggesting it is learned not inherent. Silver, whether bullets or blades, are the Lycans' only weakness, as they seem to be violently allergic to it. A new variation on this is the use of Silver nitrate bullets to inject the silver directly into a Lycan's bloodstream.
Although originally Lycans could only transform at the full moon, it is also explained that the older a lycan becomes in age, the more control he can exert over his transformation, to the point that he can change at will, possessing full mental control of his wolf form. In their wolf form, Lycans also have access to powerful jaws and razor-sharp fangs and claws, making them deadly close-quarters combatants.
A special note should be made of William, the original Lycan (or Lycan Elder, as Selene refers to him in the novelisation of Underworld: Evolution). William possessed the same physical traits as his offspring, but to a far greater degree. His strength was such that he was able to engage his Hybrid relative Michael Corvin in combat, winning at first and only being forced back due to the helicopter's machine gun - especially impressive as Michael had just killed several first-generation Lycans with ease. He was also resilient to the UV gunfire of Selene. (It should be noted, however, that the UV rounds were designed primarily for use against Vampires.) Although the rounds penetrated, they barely seemed to slow him down, and only the previously mentioned minigun seemed to have any kind of lasting effect. His muscle power was such that he was able to leap dozens of feet when escaping Selene's explosive shuriken.
Generations
William Corvinus's form of lycanthropy is the most primitive, and also the most powerful. He has the most lupine features, with a long muzzle and pointed ears giving him a marked resemblance to a real wolf. He is also far larger than his offspring. William is the most savage Lycan seen (with an insatiable appetite for rampage, according to Andreas Tanis), and also cannot revert to his human form. Unlike later Lycans, he has a full pelt of fur all over his body. It should also be noted that while every other Lycan seen in the films has black or gray fur, William's is mostly white. He has solid white eyes.
1st Generation
These Lycans were created after being bitten (or killed then came back to life as Lycans) by William. Similarly to William, they are complete savages with no control over themselves and the inability to revert to a human form. Physically, they are more humanised facially, with a shorter snout (although still longer than the second-generation Lycans) and a lack of pointed ears. They have less fur than William, but more than their second-generation Lycan descendants, with more fur around the neck and arms. They were also never able to take human form again. It was not until the second generation of Lycans were born that they were able to transform at will.
2nd Generation
These are modern (as of the first film) Lycans descended from the 1st generation. They have learned to transform back to their human form, and are able to change into lycan form when the moon is full. Those who have been Lycans for longer have learned to transform at will regardless of the moon. They resemble 1st generation Lycans, but their faces are shorter, and the least lupine in appearance. They also have far less fur than the first-generation Lycans - they are mostly hairless, aside from a thin mane of fur running down the centre of their backs.
