Once all side quests are complete, speak to Brynjolf who is wandering between the Ragged Flagon and the Cistern. Once found, follow him to the center of the Cistern where the Guild officers will initiate the Dragonborn as the new Guild Master. Once this is done, Brynjolf tells you to see Tonilia as she has something for you. Once this is done the quest will complete and the Achievement/Trophy, One with the Shadows, will be awarded.
The 'small jobs' from Vex or Delvin can still be carried out after completing this quest.
Amulet of Articulation (persuasion attempts almost always succeed and speech skill is 5-35% better)
Key to the Guild's Tribute Chest (the chest located in front of the Guild Master's Desk in the Cistern contains random loot such as gems, coins, enchanted weapons, etc.)
Objective: Speak to Brynjolf about becoming the Guild Master
I've been offered the position of Guild Master of the Thieves Guild. All that remains is to attend my installation ceremony in the cistern of the Ragged Flagon.
Objective: Proceed to center of Cistern
Objective: Become Guild Master for the Thieves Guild
Objective: Speak to Brynjolf about being Guild Master
Objective: Retrieve your Guild Leader Armor from Tonilia
With the ceremony complete, I've become the Guild Master of the Thieves Guild. As a benefit of my position, I've received a suit of Thieves Guild Leader's Armor, the Amulet of Articulation and the key to the Guild Master's Tribute Chest.
Quest complete
Trivia
This quest does not officially begin until all "special" city jobs are completed. There are four jobs, one for each walled Hold capital (Markarth, Solitude, Whiterun and Windhelm). There is no special job for Riften because the Thieves Guild already has influence in the city.
Despite being the most difficult Thieves Guild-related armor to acquire, the Guild Master's armor is inferior to the Blackguard's armor in both armor rating and enchantments. The Blackguards armor can be acquired by speaking to Glover Mallory in Raven Rock and completing the quests he offers. He will then allow the Dragonborn to unlock his treasure room with a special key, and take the Blackguard's armor along with a note to Sapphire and leveled loot.
Unlike in Oblivion, the Thieves Guildmaster is not known as the Gray Fox in Skyrim. Therefore, the last known carrier of the Gray Fox title was the Hero of Kvatch.
Bugs
This section contains bugs related to Under New Management. Before adding a bug to this list, consider the following:
Please reload an old save to confirm if the bug is still happening.
If the bug is still occurring, please post the bug report with the appropriate system template 360 / XB1 , PS3 / PS4 , PC / MAC , NX / PS5 , XS , depending on which platform(s) the bug has been encountered on.
Be descriptive when listing the bug and fixes, but avoid having conversations in the description and/or using first-person anecdotes: such discussions belong on the appropriate forum board.
Click to show
PS3 360 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. Possible fix by healing Brynjolf.
If you are at the end of the thieves guild quest line and are unable to find Karliah in the Nightingale Hall, it is most likely caused by not completing enough sidequests for Vex or Delvin Mallory. If this is the case, you will instead find Karliah at the very end of the Snow Veil Sanctum, the place where she shot you. The actual bug is apparently caused by the quest "Under New Management" never starting, so it might be possible to fix this issue using the console commandsetstage TGLeadership 50. It has been tested with the NPC in Snow Veil Sanctum and Karliah has been teleported inside Nightingale Hall, moving after few hours inside The Ragged Flagon - Cistern.
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.(Killing Shadr, while possibly more desirable, isn't actually necessary. You can simply find Sapphire and follow her back to the Cistern)
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 Tonilia 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".
PS3 360 (As of Patch 1.4) If you have completed all of the City Influence quests and fully renovated The Ragged Flagon before you complete "Darkness Returns", when you then complete "Darkness Returns" and return to The Ragged Flagon - Cistern, Brynjolf may walk up to you and initiate conversation, but this will not result in starting the "Under New Management" quest or initiate the ceremony to make you Guild Master. Attempts to talk to Brynjolf after this result in him replying that he is too busy.
Losing, selling or wearing Thieves Guild Armor appears to have no effect on this issue.
Speaking to Tonilia with or without Thieves Guild Armor on did not have any effect.
Killing Sapphire did not appear to fix this issue either.
Completing "Darkness Returns" before completing the final City Influence quest appears to prevent this issue from occurring and allows this quest to start correctly.
Delaying "Deliver Moon Sugar to Ri'saad" until after "Darkness Returns" is sufficient to avoid this problem (confirmed on PS3 360 ).
If you're in stage 4 of vampirism (without Dawnguard DLC), the NPCs (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 NPCs, because they are all waiting for the ceremony. This is no longer a problem since Dawnguard.
It's possible that after you talk to Brynjolf, and he leads you to the middle of Cistern where all other high-ranking members of the Thieves Guild are present, the initiation may be skipped and be able to proceed anyway to receive your armor from Tonilia.
360 If you finish the main Thieves Guild questline and then proceed to talk to Brynjolf, he will incessantly say he is busy, and completing the city influence quests and using the suggested solutions above does not appear to actually change anything, making the quest unstartable. Currently, there appears to be no solution to this issue.
If you have already finished all of the special jobs from Delvin Mallory previous to this quest (and possibly Darkness Returns), then you will have to return to Delvin and tell him again that you have finished the special jobs.