Emperor Dagran Thaurissan is the current ruler of the Dark Iron Clan and possible a child of Emperor Thaurissan and Modgud. Even as the leader of his clan, he is also a slave of Ragnaros, who was summoned by his father.
It was thought that he has cast a spell on King Magni Bronzebeards daughter, Moira Bronzebeard, to control her.
But in fact, Moira thinks, that Thaurissan is a great and honorable dwarf, and fell in love with him and became pregnant of him. So the heir to the Kingdom of Ironforge will be a unborn Dark Iron dwarf.