Shadow Labyrinth has 11 quests in TBC Anniversary, all open to both factions. Most need level 68: the Codex of Blood chain from Shattrath, Spy To'gun and the Soul Devices, Khadgar's Karazhan key fragment, the Book of Fel Names for Altruis and the Lexicon Demonica. The Ward of Wakening and the two Wanted bounties need level 70.

Every Shadow Labyrinth quest at a glance

QuestGiver (where)Req. levelWhat you do
Trouble at AuchindounSpymistress Mehlisah Highcrown (Shattrath City)68Report to Field Commander Mahfuun at the dungeon entrance
The Codex of BloodField Commander Mahfuun (Terokkar Forest)68Read from the Codex of Blood inside the dungeon
Into the Heart of the LabyrinthThe Codex of Blood (inside)68Kill Murmur, then report to Mehlisah on the Terrace of Light
Find Spy To'gunSpy Grik'tha (Terokkar Forest)68Find Spy To'gun inside the Labyrinth
The Soul DevicesSpy To'gun (inside)68Steal 5 Soul Devices and take them to Mehlisah
Entry Into KarazhanKhadgar (Shattrath City)68Get the First Key Fragment from an Arcane Container
The Book of Fel NamesAltruis the Sufferer (Nagrand)68Take the book from Blackheart the Inciter
The Lexicon DemonicaDavid Wayne (Terokkar Forest)67Take the Lexicon from Grandmaster Vorpil
The Ward of WakeningMorthis Whisperwing (Zangarmarsh)70Bring 10 Bogblossoms, 10 Ancient Lichen and 10 Dreaming Glory
Wanted: Malicious InstructorsNether-Stalker Mah'duun (Lower City)70Kill 3 Malicious Instructors
Wanted: Murmur's WhisperWind Trader Zhareem (Lower City)70Bring back Murmur's Whisper

Source: Questie's quest database. Shadow Labyrinth is the Auchindoun wing in Terokkar Forest, and Normal runs give Lower City reputation all the way to Exalted.

TBC Leveling 1 → 70Any character leveled to the TBC cap of 70.from 25 EURGet it done

Which quests should I pick up before entering?

In Shattrath, take Trouble at Auchindoun from Mehlisah, Entry Into Karazhan from Khadgar and the Wanted bounty that fits your run from Lower City. In Terokkar, take Find Spy To'gun from Spy Grik'tha and the Lexicon from David Wayne. Mahfuun at the entrance gives The Codex of Blood. Altruis (Nagrand) and Morthis Whisperwing (Zangarmarsh) are out of the way, so grab their quests when you pass by.

Which quests start inside the dungeon?

Two of them. Reading the Codex of Blood starts Into the Heart of the Labyrinth, which ends with Murmur's death. Reaching Spy To'gun completes Find Spy To'gun and starts The Soul Devices. Both chains are turned in to Mehlisah back in Shattrath, so you can do them in one trip.

Is the Karazhan key fragment still needed in TBC Anniversary?

Entry Into Karazhan is still in the game and sends you here for the First Key Fragment. According to Blizzard's announcement, attunements are account-wide in the Anniversary version: once one character finishes a raid attunement, that raid is unlocked for every character on the account. Alts may not need to run this step again.

How many runs does it take to finish everything?

With the right quests in your log, one full clear covers Vorpil, Blackheart, Murmur, the Codex, To'gun, the Soul Devices and the key fragment. The Ward of Wakening is a herb turn-in you can complete outside the dungeon. The Wanted bounties are separate and only worth taking on the day you run the matching version.

If you'd rather skip the dungeon grind, PewPewShop's vetted players offer TBC Raid Attunements from EUR 20 and TBC Leveling 1 → 70 from EUR 25 as play-together progression help with no bots or cheats.