i beat sunken city with 3 friends and i did not finish my task. why???
[][][]
Here are a few questions:
Were you on the "entrance sigil" at the same time as your friends, and you all went in together? You can't just port in, and get credit. You must enter through the sigil.
Were you at the last battle (killing Grubb) and were you still "alive" in the battle when Grubb was defeated? If you were not alive in the battle when he was killed, you will not receive credit for the quest.
Or, after you defeated Grubb, did you return to Marla Stinger (in Nightside: in the area right next to the Death School) where you first met her when you accepted this quest?
Open your Quest Log File, and look for the quest "To Sunken City". After you defeat Grubb, the quest automatically returns to "talk to Marla Stinger" again. You must go talk to her again.
][