Master of Kolat Towers and baelnorn
When Duhlark is seen, which is rarely, he is completely covered in a black robe, including leather gloves and a heavy hood. Little other distinguishes him from any other enigmatic mage.
Duhlark Kolat is a famous transmuter from pre-Spellplague Waterdeep who lived with his brother, Alcedor.
Duhlark is now a baelnorn, a non-evil lich who gave his life into unlife in order to protect Waterdeep. He was gone for some time after the Spellplague, but he has since returned to continue his work protecting the city he loves and to do penance for things he believes he did wrong.
He has been working with Elyas, trying to get his bearings in the world before acting to help save it.
His brother, who also attempted the turn to lichdom, did not succeed because he had used too much of his essence casting spells to enchant items and the like. Someone attached him, now a demilich, to the unliving skull of a mind flayer to use as a trap for the heroes, using vaporized Stream as some sort of catalyst. The reasons for this are still somewhat unclear.