So I completed all the Thieves Guild quests (or so I thought) and returned the skeleton key to Nocturnal and got that achievement to unlock, but I have yet to be made into the Guild leader. I did some research and found that I have to do those little quests from Delvin and Vex, and then a few city quests, then some other main quest before I am made leader of the Guild and get the achievement. My question is roughly how many of the small quests from Vex and Delvin do I have to do to get the city quests to unlock? Any help would be great, Thanks!!