Inspired by the novel, the director once considered developing a screenplay that would re-imagine the young warriors — some with superpowers — from Fengshen Yanyi as modern-day university students. He even toyed with the idea of naming this institution "Fengshen Yanyi Academy".

"I have always wished to produce a film centering on young heroes who possess superpowers and master excellent martial arts skills but live in modern society. I once planned to write such a story. But after I read The Outcast, I thought, 'It's a very mature, well-developed and amazing work.' So, I quickly abandoned my idea and shifted to The Traveller film," he says.

In early 2021, the film launched a nationwide casting campaign, auditioning over 1,000 candidates and selecting three finalists for each character. These finalists underwent months of rigorous training, which included learning martial arts skills such as tai chi and shequan (snake fists), as well as performance techniques.

Those who ultimately secured the roles underwent specific training to fully embody their characters. Actor Hu, portraying the protagonist Zhang, had to practice talk show techniques as his character is talkative and slick. Actress Li underwent training to speak minimally within a month as her character Feng is a powerful fighter of few words.