Zarlandris

A young black dragon, child of the ancient dragon Malestorix who drove the dwarves out from the ancient dwarfhold beneath Dragonwatch. He led the cult of scales who planned to set off explosives in Dragonwatch and siphon the souls of the dead to Tiamat in Avernus. They hoped to grant her the power to reclaim Avernus from Bel the pit fiend (current archduke of Avernus).
He was killed by the Covenant of the Veiled Coin in the ruins beneath Dragonwatch.