The term "mulatto" is an outdated and offensive term for a person of mixed European and African ancestry. Milton Reid, who portrays the character called "the mulatto," is of Scottish and Indian heritage.
In certain scenes featuring the "Phantoms of the Marsh," only the glowing portions of the riders and their horses are superimposed over a background plate. While this achieves a spooky effect, it leaves the rest of the men and their horses completely transparent.
Glow-in-the-dark paint is a 20th century invention. In the movie it is used in the year 1792.
The tavern scenes feature a modern violin.