Count Orlok
Since Nosferatu's producers did not bother obtaining permission from Bram Stroker's widow to adapt Dracula, they made some changes in a failed attempt to skirt potential copyright claims. Count Orlok, of course, stands in for Count Dracula. Orlok doesn't have a particularly aristocratic air, as direct F.W. Murnau clearly reveled in the opportunity to create a brand new, grotesque villain with terrible social skills, terrifyingly elongated physical features, and two rat-like teeth.
Thomas Hutter
Thomas Hutter is more or less the protagonist of this film, and very much the party responsible for ushering Count Orlok and his plague to the little city of Wisborg. One of the central plot lines of the film revolves around Hutter shedding his cosmopolitan, secular worldview as he develops an understanding of the ancient evil he has summoned. As far as this Dracula adaptation goes, Hutter is the Jonathan Seward character.
Ellen Hutter
Ellen is the sin-free, virginal wife that Thomas leaves behind in his hometown to pursue the real estate lead. She will become the subject of Count Orlok’s infatuation, and his quest for her blood will result her keeping him alive until sunrise, killing him. Ellen stands in for Mina Harker in this adaptation.
Knock
Knock is a particularly fascinating figure in the framework of Nosferatu. The audience first comes to know Knock as the real estate agent who employs Thomas Hutter to finalize the deal with Count Orlok. Later, we learn that Knock is Orlok's minion, and has sent Hutter to retrieve him as part of a ploy. Knock turns out to be this film's stand-in for the fly-eating, lunatic asylum inmate Renfield.
Harding
When Hutter takes off for Transylvania, he entrusts the care of his wife Ellen with his close friend Harding and Harding's sister, Annie. Due to the relationship between the characters and the fact that Harding appears to be somewhat well-off financially, he is usually viewed as being the equivalent of the novel’s Sir Arthur Holmwood.
Professor Bulwer
Bulwer is the stand-in for Professor Van Helsing here. Bulwer has none of Van Helsing’s extensive knowledge of vampirism and plays no part in the tracking down and dispatching of Count Orlok. Yet, he is the one that first realizes what evil is plaguing the city. His lecture on parasitism in the middle of the film does help flesh out one of the main themes of the film—the tension between the modern and the ancient—as his contemporary understanding of science uses the new biological worldview to shed light on an ancient physical impulse.
The ship's captain
We mainly know the ship's captain as the man who discovers the outbreak of the plague on his own ship. Knowing that even he will die, he ties himself to the ship's steering wheel as a final act.
Prison Guard
The prison guard is mainly presented as an ineffective representative of the government. He's incapable of containing Knock and therefore incapable of protecting his city from the evil that Knock's master will rain upon it.
The Innkeeper
When we meet the Innkeeper, it becomes quickly clear that he as a country person understands something that the city slicker Hutter just isn't capable of comprehending. The Innkeeper knows there is a great evil in the countryside, but seems to be all too aware that he'll be unable to convince Hutter that there's any truth to that belief.
The Rats
The rats don't have any speaking role, but they are crucial players in the story as the entity that perpetuates chaos in Wisborg. Without the rats, the Nosferatu may not have slipped in so undetected. The rats, of course, bear a lot of likeness to our vampire, so they act as an important proxy for our villain.
