In Vietnamese mythology, what dragon is said to be the ancestor of the Vietnamese people through Lạc Long Quân?

In Vietnamese mythology, Dragon King Lạc Long Quân is the dragon ancestor of the Vietnamese people.

Lạc Long Quân is a legendary ruler and dragon lord in the origin story of the Vietnamese people. He marries Âu Cơ, who is described as a mountain fairy or immortal. Their union produces one hundred eggs, from which one hundred children hatch. The couple later separates because their natures and homelands differ: Lạc Long Quân returns toward the water, while Âu Cơ and many children go to the mountains.

The story explains the traditional idea that Vietnamese people are descended from both a dragon and a fairy. Their eldest son is associated with the Hùng Kings, the legendary early rulers of Văn Lang.

Lạc Long Quân is not simply the same figure as an anonymous Vietnamese water dragon. He is a named culture hero and ancestral ruler whose dragon identity is central to the national origin legend.