They go into the mysterious underworld beneath Chinatown , where they face an ancient sorcerer named David Lo Pan ( James Hong ) .Although the film was originally envisioned as a Western set in the 1880s , screenwriter W. D. Richter was hired to rewrite the script extensively and modernize everything .
In the film Big Trouble in Little China , James Hong portrays an ancient wizard , David Lo Pan , who resides in the underworld below Chinatown .