How to Become a Werewolf in "Dragon Age: Origins"by Megan KoosUpdated September 22, 2017
In "Dragon Age: Origins" werewolves stalk the forests and hunt the Dalish you are sent to recruit. Though the werewolf curse is contagious, it is not possible for the main character or any of his or her allies to contract the disease. In short, there is no way to become a werewolf in the game. You can, however, choose to side with the werewolves in the main plot quest "Nature of the Beast." Doing so will substitute an army of werewolves for the Dalish in the final battle against the Archdemon.
Agree to parley with the Lady when confronted by the Gatekeeper. Be solicitous in your conversation with her. She will eventually ask you to help her convince Zathrian to end the curse.
Select "(Persuade) I have another plan. Kill the elves. Kill Zathrian."
Assure the Lady you will help them assault the Dalish camp by selecting "The Grey Wardens need allies. I'll take you over the elves." Depending on who is in your party at the time, you may have to convince them this is a good plan.
Select confrontational dialogue choices when the werewolves talk with Zathrian in the Dalish camp such as "You deserve whatever you get here, Zathrian" or "I think an army of werewolves will be very handy." Zathrian will refuse to end the curse.
Kill the Dalish, including Zathrian. At the end of this fight, the Lady will ask what you want in return for helping them. Any of the three dialogue options here should get you the same response: the werewolves will agree to fight by your side against the darkspawn.
You can gain or lose influence with your party members by selecting this course of action. Convincing them (via persuade dialogue options) that you are correct can mitigate the damage with some companions, but not all of them.