Find Milten in the northern part of New Haven to start the quest line. Walk up to him and say Milten join and double click him. He will give you the quest “A New Life” with the following text.
Joining the fire mages requires you to relinquish all of your old possessions and start a fresh journey with an open mind. Sell everything you have and donate the proceedings to the church.
You are given the task to join a city and are rewarded with 200 gold and 1000 experience upon completion.