The Snake King's Child.

In a small village, Nhi comes across a Snake Immortal and falls in love with him. She becomes pregnant by the snake, but does not tell her husband. When he discovers the truth, he kills both Nhi and the Snake Immortal. One of the small snakes escapes from Nhi's abdomen, and is brought up by another immortal. Slowly the snake grows up to be a beautiful woman, who sets out to develop another relationship.