- Corpsing: During the scene where Lan Wangji gives Wei Wuxian a piggyback ride, upon a closer look the audience can see that Xiao Zhan and Wang Yibo are already chuckling.
- Dawson Casting:
- Around the time The Untamed aired, the actors for Lan Sizhui, Jin Ling, and Lan Jingyi were 20, 22, and 24 years old (respectively), whereas their characters are only around 15 to 17 years old.
- Many of the actors were older their characters in the flashback arcs, typically being in their mid or late twenties whereas their characters were in their teens to early twenties.
- Directed by Cast Member: Bian Jiang (Lan Wangji's voice actor) is also the voice director of the series.
- Never Work with Children or Animals: In the scenes where Fairy would chase Wei Wuxian, the crew got a hard time getting the husky to chase Xiao Zhan unless they baited it with sausages.
- Promoted Fanboy: Xuan Lu was already a huge fan of the novel long before she got cast as Jiang Yanli.
- Role Reprise:
- Some of the voice actors from the donghua and the audio drama adaptations of Grandmaster of Demonic Cultivation: Mo Dao Zu Shi return in the Live-Action Adaptation to dub over the actors playing the characters they voiced. There's Lu Zhixing as Wei Wuxian, Bian Jiang as Lan Wangji, Qiao Shiyu as Wen Qing, Tang Shuiyu as Jiang Fengmian, and Qiu Qiu as Wang Lingjiao.
- The Japanese voice actors of the donghua dub (with a few of them also coming from the audio drama dub such as Hikaru Midorikawa (Jiang Cheng) and Toshiyuki Morikawa (Lan Xichen)) also voice their characters in Japanese dub of this live-action adaptation.
- Separated-at-Birth Casting:
- Although they were cast as either uncle and nephew or father and son, the resemblance between actors Qi Peixin, Zhu Zanjin, and Cao Yuchen is so uncanny that — given their ages in Real Life — you'd expect all three of them to be long-lost brothers.
- Ji Li (Nie Huaisang) and Wang Yizhou (Nie Mingjue) have such similar facial features that from appearance alone, they can convince any unknowing passerby that they really are brothers.
- Star-Making Role: The Untamed served as a major popularity boost to most of the actors, especially for Xiao Zhan and Wang Yibo. By the end of 2019, both had already become two of the highest-rated actors in China.
- Throw It In: According to an interview, some of the cast members' mannerism or improvisations made it into the show.
- Jiang Cheng's eye-rolling wasn't directed, he just did it because it seemed to fit the situation.
- Lan Jingyi's actor says that when he dropped his chicken wing it was something he and Lan Sizhui's actor claimed happened as a coincidence, but thought would be funny and it was kept in the final cut.
- Nie Huaisang's actor was told to just dust off Jin Guangyao's hat, but he accidentally touched the blood on it. The director liked it so much he filmed an extra scene of Nie Huaisang looking at the blood on his hand that made it into the final cut.
- What Could Have Been:
- The series was implied to have originally featured a romance between Wei Wuxian and Wen Qing. But after severe backlash from the fans, the script was rewritten almost completely.
- Several of the actors initially auditioned for different roles:
- Most notably, Xiao Zhan, Song Jiyang, Wang Zhuocheng, Ji Li, Guo Cheng, and Qi Peixin originally auditioned for the role of Xue Yang. They were cast instead as Wei Wuxian, Xiao Xingchen, Jiang Cheng, Nie Huaisang, Lan Jingyi, and Jin Ling, respectively; although Song Jiyang managed to briefly play Xue Yang when he was pretending to be Xiao Xingchen.
- Zhu Zanjin, Yu Bin, and Cao Yuchen auditioned to play Lan Sizhui, Nie Huaisang, and Lan Xichen, respectively. They were ultimately chosen to play (in the same respective order) Jin Guangyao, Wen Ning, and Jin Zixuan.
- The filming crew originally planned to have Wang Haoxuan wear fangs since Xue Yang has canine-like teeth, but the idea was scrapped because he ended up looking too vampiric, and it got in the way when the actor would speak his lines.
- According to Zhu Zanjin, Fatal Journey was originally going to be about the Venerated Triad, but the idea was scrapped because any plot they had in mind was too large to be covered by a movie's runtime length.
Trivia / The Untamed