Lycanthropy

Lycanthropy is a disease that causes the victim to transform into a were-creature, and is generally contracted by being bitten by one. All races can contract lycanthropy; however, Altmer, Argonians, Bosmer, and Redguards are resistant to Lycanthropy but are not immune to it. Lycanthropy itself was created by Hircine, who now serves as the guardian of the people infected with lycanthropy. It is believed that a cure for this disease exists in the Glenpoint foothills of High Rock. This disease gives the infected a bloodlust, meaning they must kill every time they transform.

Types
The form someone takes upon contracting lycanthropy varies according to their species. As there are many different species of man, mer and beast throughout Tamriel, there are many according types of lycanthropes.

Cure for Lycanthropy
At the end of the Companions Questline, a Radiant Quest: Purity becomes available for those adventurers who wish to rid themselves of the beast within. As a part of that quest you must cut off the head of a Glenmoril Witch, bringing it into the depths of the Tomb of Ysgramor, draw the spirit of the wolf from your body, and defeat it. Once the ritual is complete, your cure is permanent, and you cannot contract Lycanthropy again.

Bugs

 * Even after cleansing yourself of your lycanthropy, guards still comment that "Your wolfish grin is unsettling", and "Is that hair coming out of your ears?", and when going to your General Stats it's still counting your days as a Werewolf, even though the ability to change is not under Magic --> Powers, and trying to fight your wolf spirit again isn't possible.

Appearances

 * The Elder Scrolls II: Daggerfall
 * The Elder Scrolls III: Bloodmoon
 * The Elder Scrolls V: Skyrim