Actress Janet Gaynor and actor Charles Morton (who played two of the main characters).
F. W. Murnau is one of the most beloved directors of the silent era, sometimes touted as one of the all-time greats. His 2 most well-known works, Nosferatu (1922) and Sunrise (1927) both very narrowly avoided becoming lost films themselves. Nosferatu was ordered by the estates of Bram Stoker (author of Dracula) to have all copies destroyed due to claims of copyright infringement. The film only exists thanks to film collectors who held onto their copies, making it the first film to ever be saved by piracy. Sunrise's master print was destroyed in a studio fire in 1937 and now only survives in a grainy copy that has been quite a chore to keep preserved.
Sunrise was the first of Murnau's 4 US Movies, while the other two City Girl and Tabu have survived 4 Devils, has not been so fortunate. The film was his first that was done under the eyes of the studio, stealing away the artistic freedom that made Sunrise so great. The film's plot involves 4 trapeze performers who were orphaned as children, who's leader Charles falls for a Vamp threatening the close relationship of makeshift family. The film was released as a silent film, and then later a sound version was released (this was also done to City Girl but the sound version is now lost as well). Sadly, it was one of Murnau's final films before his untimely death in 1931 at age 43. It was a massive failure at the box office, one of the worst for a major feature film at the time. Amazingly, despite how drastically different the film was from Murnau's other works, it was still met with glowing reviews.
Neither the sound nor the silent version of 4 Devils has survived. It is speculated that actress Mary Duncan borrowed the final surviving copy and failed to return it to 20th Century Fox. She reportedly misplaced it, though her heirs may have found it. On Sunrise's 2003 DVD issue, a slide show of the film was included as a special feature. It featured the script played out in its entirety, with rare production photos and voice narration to accompany it. This, however, has become a rarity as well, as the DVD was mail-order only an has been long out-of-print. This has resulted in the DVD commanding high prices and the feature is rarely seen (impossible to find online).