Before he meets Au Co, the Linh Nam Chich Quai gives Lac Long Quan a separate cycle of heroic deeds in his own right, clearing the land of three monstrous spirits collectively remembered as the Ngu Tinh. Ngu Tinh, a giant fish demon with a centipede-like body large enough to be mistaken for a ship's sail, terrorized fishermen along the coast until Lac Long Quan cut it into three pieces, its head becoming a mountain, its tail forming the beach around what is now Bach Long Vi island, and its body carried off to a distant land. Ho Tinh, a nine-tailed fox spirit, had lived for centuries beneath a mountain west of what is now Hanoi, luring travelers, particularly young women, into its cave; Lac Long Quan destroyed its lair and drove floodwater into the cave to finish it. Moc Tinh, a centuries-old tree spirit capable of taking human form, sabotaged farmers' fields by night until Lac Long Quan felled its host tree and scattered its remains across separate regions to prevent it reforming. The three victories are told as a connected sequence establishing Lac Long Quan as a land-clearing culture hero in his own right, distinct from and prior to his role as husband to Au Co and father of the Hung Kings' line, presented as the reason the land was made safe for human settlement before that dynasty's founding.