Li-En

リィエン Rīen

Li-en is Li-Akron's daughter in Hong Kong. Her father intentionally ended every relationship Li-en ever had. She stated, "Every guy I dated left me as soon as they found out who you are." I believe her father acts this way because he is protective of his daughter. Won Rei, however, did not leave her. She teaches Won Rei martial arts to make him unbeatable, and she remains with him. Li-en also tends to Won Rei's wounds.
One day, she discovers that Won Rei wants to stop fighting because he did not want her to get hurt. She visits 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 is then sent to Japan to her grandmother's house.
While in Japan, he escapes from two of her father's employees. She spots a spell book and steals it from Kiyo. She does apologize to Kiyo and asks for his help to rescue 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 the same two.
Kiyo and Zatch assist Li-en in reaching 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, she admits that she loves Won Rei. Won Rei tells her to go home, but she stands in front of the cell. Won Rei also tells her to move, and 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 exits the cell using the Go Boren spell, Won Rei intends to send Zabas back to the mamodo world. After Zabas is knocked out, Won Rei carries her toward the boat, and they see Li-en's father. Li-en's father allows his daughter to go with Won Rei.
Later in the series, they encounter Dr. Riddles. The anime depicts this quite quickly. Also, when they arrive in 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.