Venetica

To become a member of the Hooded Wings, go to the Outer City and locate the Hooded Wings headquarters. It's the house next to the garden with the lion statue in the eastern part of the city. Go inside and head upstairs to talk to Master Deimos, and ask him about joining up. You'll need to complete a quest first as a test of your ability, so go down to the basement and talk to Grimm just inside the door to the basement. He'll give you a letter to deliver to somebody named Hod on the Outer City rooftops.

Head into the catacombs, take a right and wade through some water until you reach a skeleton lying on the ground. Take another right, then stay to the left and enter the water. Swim left and follow the cavern wall until you come to a small, and hard to see, opening in the wall. Go in here and follow along to a larger hallway. Take a right and go up a platform with a door at the top. Go through the door to somehow find that you've gone from the sewers to the rooftops. Locate Hod on the balcony and give him the letter, then return to the Hooded Wings headquarters. Talk to Master Deimos when you arrive to join the guild.