Undercity: The Promise

After speaking to Sihek and inspecting the corpses near him, go outside the city to the southeast and find the Golden Snakes. Kill them and loot their Golden Blood until you have 10, then a place called Ennead’s Folly will appear. Go inside and explore the Mage Clan ruins.

Once you reach the final chamber, inspect the chest and the book, then pick up the dagger and return to Sihek in Kurast and speak to him.

After he reveals the existence of a possible progenitor, he’ll send you back to the Undercity, so return to the brazier and start another run. This time, it will send you to the Temple district, and the final boss will be Yoche, The Golden.

During the fight, Yoche will channel power through the serpent statues, so knock them down one by one to cut him off and continue the fight. If your damage is high enough, you can kill him before he does this, however. Good luck!

Once you’ve defeated Yoche, you’ll complete Undercity: The Promise, and begin Undercity: Starving Pride, the final quest in the chain to unlock the full potential of The Undercity.