He starts the quest  .
See List of Undercity NPCs.
"I am an officer of the city, working in the capacit of the Undercity's census. Since our liberation from the Scourge, we have tried to keep an accurate track of our city's populace. Through arcane discipline, I am able to access these records. If you have buisness with me accordingly, please proceed. You should know if you do, at any rate."