Li-en is the daughter of Li-Akron in Hong Kong. Her father deliberately sabotaged every relationship she ever had. She once said, "Every guy I dated left me as soon as they found out who you are." I believe her father does this because he's overprotective of his daughter. However, Won Rei didn't leave her. She teaches Won Rei martial arts to make him unbeatable and stays by his side. Li-en also tends to Won Rei's wounds.
One day, she discovers that Won Rei wants to stop fighting because he doesn't want her to get hurt. She goes to her father, and Li-Akron tells her, "He's in a jail miles south of here... on Yougan Island. His cell is atop rugged mountains, and I've sent several employees as security guards." She gets sent to Japan to her grandma's house.
While in Japan, he escapes from two of her father's employees. She finds a spell book and steals it from Kiyo. She apologizes to Kiyo and asks for his help to save Won Rei. While waiting for the boy with the red book (Kiyo), the two employees catch up with her. The Zaker spell, Zatch's first spell, shocks them both.
Kiyo and Zatch help Li-en reach Won Rei, but a mamodo named Zabas and his human partner are at the top of the mountain. She reaches the cell where Won Rei is held and eventually admits that she loves him. Won Rei tells her to go home, but she stands in front of the cell. When he tells her to move, she says, "What's wrong Won Rei? You said you didn't love me... so why are you worried about me?"
Zabas calls Li-en worthless, and when Won Rei gets out of the cell using the Go Boren spell, he wants to send Zabas back to the mamodo world. After knocking out Zabas, Won Rei carries her toward the boat, and they see Li-en's father. Li-Akron lets his daughter go with Won Rei.
Later in the series, they encounter Dr. Riddles, though the anime shows this briefly. When they reach South America, they meet Tia, Kanchome, Ponygon, and Zatch. The last time I saw Li-en and Won Rei, they were in the ruins with Tia and Megumi.
