Becoming a WerewolfEdit
There are several methods to contract Lycanthropy. It can be given to its victim by a scratch from a werewolf or even bought in the Crown Store.
To contract Sanies Lupinus, the Vestige can be infected by another player or by an enemy NPC.
By another playerEdit
The easiest way is most likely getting infected by another player. If the Vestige does not have friends with the sickness, many guilds can offer the service for a cost. To infect someone else with Sanies Lupinus, the player must have the Passive Skill Bloodmoon, from the Werewolf tree, unlocked. The player that has this skill can only transmit the sickness once every seven days and players already infected with Sanguinare Vampiris (Vampires) cannot be infected with Lycanthropy. Provided the players are not stopped by these conditions, they sickness can be transmitted in the Ritual Site of their alliance (shown to the already infected player as the option to activate a synergy). After being infected, the quest Hircine's Gift will be added to the journal.
By an enemy NPCEdit
Even though werewolves make several appearances throughout the game, not all of them can infect the Vestige with Sanies Lupinus. Only a certain variety of werewolves are able to transmit the sickness. These enemies are extremely rare and are known to spawn in the highest level territory for each alliance (Bangkorai, Reaper's March and The Rift), at night and with full moon. These enemies can be really hard to find because of the previous conditions and also because of other players that constantly hunt them to acquire the sickness or to raise the price of it in the market. If the Vestige gets infected, the quest Hircine's Gift will be added to their journal, asking them to travel to the Ritual Site.
The Ritual Sites are very important places in the process of becoming a Werewolf. They are located in the highest level territory for each alliance: Bangkorai for the Daggerfall Covenant, Reaper's March for the Aldmeri Dominion and The Rift for the Ebonheart Pact (Werewolves that can infect the Vestige spawn in these same regions). They are the locations in which the quest Hircine's Gift is achieved.
- U7: Fixed an issue where you could unintentionally contract both Vampirism and Lycanthropy at the same time. 
- U7: From Update 7 onwards, it is only possible to transform into a werewolf with Werewolf Transformation slotted. 
- U7: Also in Update 7, it is no long possible to go Fishing whilst in Werewolf mode. 
- The Elder Scrolls II: Daggerfall
- The Elder Scrolls III: Bloodmoon
- The Elder Scrolls V: Skyrim
- The Elder Scrolls Online