Under New Management

This is the final quest in the Thieves Guild for Skyrim. You accept the role of Guild Master for The Thieves Guild.

It requires you to have done all special jobs from Delvin Mallory (not including Larceny Targets) and the entire chain of main quests.

Speak to Brynjolf who is wandering around between The Ragged Flagon and the Cistern and follow him to center of the Cistern where the guild officers will initiate you as guild master.

Rewards

 * Guild Master's Armor Set (35% pickpocket, 35% lockpick, 50 points carry capacity, 20% better prices)
 * Amulet of Articulation (persuasion attempts almost always succeed, 20% speechcraft increase)
 * Key to the Guild's Tribute Chest (located in front of the Guild Master's Desk in the Cistern)

Bugs

 * If you have completed the quest Under New Management before all special jobs Brynjolf may disappear. Rendering you unable to complete the quest and become Guild Master. This bug has been seen on the PS3 and 360 versions.
 * This quest may not be able to be completed if you lost all of your Thieves Guild Armor without upgrading any of it, as the dialogue option from Tonilia to receive your Guild Leader Armor will be unavailable until a piece of the Thieves Guild Armour is upgraded.A new set of armor can be found in the training hall.
 * The quest will prompt you to proceed to the center of the cistern. All NPCs present will accordingly gather around you, but not say nor do anything. Possible fixes:
 * The thief Sapphire seems to be required at the ceremony for it to begin. If you find yourself unable to complete Shadr's "Miscellaneous" quest involving Sapphire, find Shadr by the Riften Stables and quietly kill him. This will fail his quest, but free Sapphire to be present at the ceremony, allowing it to begin.
 * Try to speak to Karliah and Brynjolf in front of you with you in the center of the room and the game should tell you "This person is busy". After a few seconds, the ceremony should start, with Brynjolf speaking first.
 * Wait for 1 hour and it should kick Brynjolf into speaking and having the quest to continue.
 * Talk to Tonilla and she will say you should be attending the ceremony. Go back to the center of the cistern room and the ceremony will be performed.
 * Be kicked out of the guild and complete the quest Reparations.
 * If you're in stage 4 of vampirism, the NPC's (not from the Thieves Guild) that enter the room will attack you on sight. You can complete the quest, but you'll be attacked. It's much easier to just go feed and then do the ceremony. Keep in mind that you can't feed on the Thieves Guild NPC's, because they are all waiting for the ceremony.