Shui Ruohan íV (Nicky Wu) / (Wu Qilong)

A professional killer, aged 25, known as Mr. Jade-Flute, worked for the East Yard -- the emperor's secret police agency. As an orphan adopted by Cao Youxiang, Ruohan was fiercely loyal to his adoptive father. At the age of ten, he was sent to Japan to be trained as a ninja. Chilly and melancholy most of the time, he was aware that as a hit man, he could never be free to love anyone. However, he fell in love with Lui Jianping when working as an undercover agent in her house with an eye to stealing a key to the emperor's tomb, which he believed her family to possess. Unfortunately, because Jianping and his adoptive father were from opposing camps, he would later be forced to have a confrontation with her.
Lu Jianping íV (Vickie Zhao) / (Zhao Wei)

The only daughter of the Secretary of Defense, aged 18, was a pretty and spirited girl. She was bold and optimistic by nature and always cheerful. Nothing seemed to bother her for too long. Since she was brought up as a boy, she was very active and liked to dress herself as a man. When her father was put in jail, she sought shelter in the Shaolin Temple and managed to greatly improve her kung fu skills. However, she fell in love with Ruohan, who was her enemy. Eventually she would be forced to confront him.
Zhu Yulong íV (Kevin Lin) / (Lin Jianhuan)

A royal prince, the second eldest son of the emperor, liked to walk among the public as a commoner. A handsome and suave young man, he made the acquaintance of Jianping in a tavern and was drawn by her straightforwardness and free spirit. When finding that Jianping was actually a girl, he was so pleased with this that he immediately asked his father, the emperor, to make her his wife. It turned out that Jianping escaped because she wasn't interested in becoming a royal princess, unaware that Yulong was the prince himself. Feeling humiliated and heartbroken, the prince decided to run away with her and do his best to protect her along the way.
Yukiko alias Bai Ruixue íV (Liu Zi)

Ruohan's fellow apprentice, known as Lady Scorpion, was also a Japanese ninja. They had trained together since they were little and Ruixue had always cared for Ruohan. To her disappointment, Ruohan viewed her as nothing more than a sister and rejected her affection. When she found that Ruohan fell in love with Jianping, out of jealousy, she tried to kill Jianping to win her love back.
Wu Ma íV (Gu Baoming)

Though being a man, he was Jianping's caretaker and bodyguard. Fun-loving, easy-going but always loving and thoughtful, he was like another parent for Jianping. As a kung fu master, he always tried his best to shield Jianping from harm.
Song Yinniang íV (Lin Fangbing)

She was a middle-aged woman who collected leftovers in the Shaolin Temple. Haughty, rude, reclusive, and short-tempered, she often fought with people over trivial things. However, she seemed to have a special affection for Xiaolong.
Xiaolong íV (Cao Jun)

Abandoned as a baby at the gate of the Shaolin Temple, he was brought up as a monk. Though still at a tender age, he was very mature and talked like an adult. He showed a gift for kung fu and was a fast learner.
Xiaofu íV (Hao Shaowun)

Xiaolong's fellow apprentice and a cheerful boy, he was sent to the Shaolin Temple to be a monk when he was young because his parents were too poor to feed him. His favorite pastime was eating, so he was visibly overweight. However, he had a gift for the practice of medicine and was often able to cure patients after trial and error.
Cao Youxiang íV (Liu Shun)

Cold-hearted and ruthless, the chief eunuch was the head of the East Yard, the royal secret police agency. In order to obtain the three star-shaped keys to the tomb of the founding emperor, he would do anything and kill anyone in his way.