Keep Le Faye (as listed on the world map), but he is on the 3rd floor, not the 2nd floor. (You have to go up 2 flights of stairs to reach him.) Confirming to reach him you go to Catherby. Then "hide in" the crate that is directly outside northeast of the candle makers shop. It will be the only crate that gives you a "hide in" option. You will then be transported to the dock at Keep Le Faye and all you have to do is "go back out" of the crate you were hiding in. You can then enter the Keep through the dock doors. If you try to walk to the Keep and use the entrance at the west side the Renegade Knights will not let you in and it is locked.
Leader of the Renegade Knights.
If you kill him during the quest, Morgan LeFaye comes to his rescue and will give you whatever you want not to kill him.