Sunny's sister, Kannin, made her first appearance on Into the Badlands in the latest episode, played by Chinese-American actress and former Olympic gymnast Eugenia Yuan. Interestingly, Yuan has deep connections to the martial arts genre, and not just through her own work in movies. Yuan is the daughter of Cheng Pei-pei, a martial arts legend known to many as the "Queen of Swords", and the first major female martial arts star.

Sunny's sister is one of the season's most important mysteries. Earlier in Into the Badlands season 3, Sunny was told that he had a sister named Kannin who helped him escape from Azra several years ago. Despite his efforts to learn more about her, Sunny has been unable to find out what happened to her after Azra was destroyed by the Black Lotus. After being captured by the Black Lotus in "Black Lotus, White Rose", Sunny finally reunites with his sister, who has been a member of the secret cult since she was recruited as a child.

Related: Exclusive Into the Badlands Clip: Sunny Versus the Black Lotus

The actress who plays Kannin is no stranger to the martial arts genre. Eugenia Yuan has appeared in a handful of martial arts films, including Crouching Tiger, Hidden Dragon: Sword of Destiny and The Man with the Iron Fists 2. Her mother, on the other hand, is a kung fu icon who starred in dozens of martial arts movies in the 1960s and '70s.

Chinese actress Cheng Pei-pei rose to stardom in 1966 with her role as Golden Swallow in King Hu's Come Drink with Me. In Come Drink with Me, Cheng Pei-pei's Golden Swallow is a one-woman army who effortlessly wipes out a large number of swordsmen in an effort to rescue her brother. The film is widely regarded as one of the best and most influential kung fu films of all-time. Come Drink With Me served as the inspiration for Ang Lee's Academy Award-winning classic, Crouching Tiger, Hidden Dragon, which featured Cheng Pei-pei as the villain, Jade Fox. At 72, the actress is still active in the industry, and will next appear in Disney's Mulan in 2020.

Her work is credited with revolutionizing the martial arts genre. Before Come Drink with Me, kung fu films typically featured male actors in the lead roles. Cheng went on to play the main character in several films in the years that followed, including The Lady Hermit, The Jade Raksha, The Lady of Steel, and several more. Over the years, her warrior woman image earned her the title of "Queen of Swords". Her work in the industry has also set the standard for other female martial arts stars, such as Michelle Yeoh. The link between Into the Badlands' Eugenia Yuan and this martial arts legend is easy to miss, but it provides a fun connection between the AMC series and a legendary pioneer of kung fu cinema.

Next: Into The Badlands Killed Off [SPOILER] To Streamline The Final Season