Cathy Ames
The most evil character in the novel, Cathy (who is referred to as "Kate" in the second half of the novel) has no conscience whatsoever. A direct representation of Satan himself, Cathy lacks an essential human quality. After murdering her parents by setting fire to their home, she becomes a prostitute and the mistress of Mr. Edwards.
Adam Trask rescues Cathy when Edwards leaves her for dead, but after giving birth to twin sons, Cal and Aron, she shoots Adam when he attempts to stop her from leaving. She takes a job as a prostitute and poisons the brothel-owner, Faye, in an effort to take over the business. She gives her whores drugs, encourages sadomasochistic sexual practices, and blackmails her customers. Late in life, she commits suicide after meeting her son, Aron.
Abra Bacon
As a child Abra falls in love with young Aron Trask, but she later realizes that he is only in love with a glorified image of her. The daughter of a crooked Salinas politician, she wonders if a parent's evil can be inherited. However, she finds psychological surcease from Lee, whom she loves like a father.
Edwards
Edwards leads a double life: he runs a New England prostitution ring, but is married to a religious wife who believes that he runs a reputable business. He falls in love with Cathy after she approaches him for a job, but beats her severely and leaves her for dead after he finds out that she killed her parents.
Ethyl
Ethyl is a prostitute who sees Kate burying the empty poison bottles that she used to kill the brothel-owner, Faye. Her attempts to blackmail Kate fail.
Samuel Hamilton
The much-beloved Hamilton Family patriarch, Samuel Hamilton mentors and guides Adam Trask. He is contrasted with Cyrus, the dishonest Trask Family patriarch who commits the novel's original sin.
An Irish immigrant, Samuel demonstrates the positive principle of life. Although he farms the most barren land in the Salinas Valley, he educates himself, fathers nine children, and enjoys life until falling into despair after the death of Una, his favorite daughter.
Samuel Hamilton was, in fact, the name of John Steinbeck's grandfather. The character Samuel experiences initial distrust from his California neighbors, but over time becomes a highly respected and much appreciated member of the community. Although he never achieves material wealth, he is the happiest of all of the characters.
Dessie Hamilton
The most beloved daughter of Samuel and Liza Hamilton, Dessie opens a successful dressmaking business in Salinas, but falls in love with the wrong man and becomes depressed. Seriously ill, she is forced to close her shop and move back to the family ranch where her brother Tom inadvertently causes her death by giving her the wrong medicine.
Liza Hamilton
Samuel Hamilton's wise wife, and an excellent mother to the nine Hamilton children. Liza's no-nonsense attitude inspires her to work hard.
Olive Hamilton
A character based on the real-life mother of author John Steinbeck. The daughter of Samuel and Liza Hamilton, Olive becomes a schoolteacher and a loving mother.
Tom Hamilton
Samuel's depressed son and a poet, Tom can't seem to find his way in the world. Tom remains on the farm after his parents die and accidentally causes the death of his sister Dessie. He kills himself out of guilt.
Una Hamilton
The introspective daughter of Samuel and Liza Hamilton, Una marries a poor photographer and moves to Oregon, where she dies in poverty. Her death causes the beginning of Samuel's demise.
Will Hamilton
Samuel and Liza Hamilton's successful, level-headed son who succeeds in business, Will sells the first automobiles in the Salinas Valley and becomes Cal Trask's business-partner during the war.
Lee
The Chinese-American cook and housekeeper for the Trask family, Lee is forced to speak in the Chinese pidgin dialect that enables him to survive in America. An orphan, he raises Adam's children after they are abandoned by Cathy.
A scholar at heart, he remains a constant friend to Samuel Hamilton and Adam Trask, aiding them in their scholarly debates. He researches the Cain and Abel story and proffers the novel's central concept of "thou mayest."
Adam Trask
Adam Trask, one of the protagonists of East of Eden, is an honest man who transforms from a dreamy-eyed youth into a deeply caring father to Cal and Aron.
The son of Cyrus Trask, Adam falls in love with Cathy Ames when she wanders onto his farm. A representation of the biblical character Abel, who was stoned to death in a jealous rage by his brother Cain, his deathbed blessing of his son Cal validates timshel, a concept that denies the notion of predestination and authorizes free choice.
Alice Trask
The mother of Charles Trask, Alice treats Adam as her own son after his biological mother dies. She rarely talks, and smiles only when no one can see her. Adam presents her with little gifts, but she believes them to be from her own son, Charles.
Aron Trask
The son of Adam and Cathy Trask and the twin brother of Cal, Aron grows up to be deeply religious. He plans to enter the ministry in an attempt to escape the sinful world. He is Adam's favorite son and is in love with Abra Bacon. When his jealous brother Cal tells him that his mother is still alive and living as a prostitute, he joins the Army during World War I and dies in France soon after.
Cal Trask
The dark-haired son of Adam and Cathy, Cal (or Caleb) is deeply jealous of his seemingly perfect twin brother, Aron, and is the novel's second Cain figure. He indirectly kills his brother Aron by causing him to enlist in the Army. Ultimately, he represents the concept of timshel, the idea that people can overcome their backgrounds and choose to live free, moral lives.
Charles Trask
Charles' father, Cyrus Trask, favors his son Adam's gift of a puppy over Charles' gift of an expensive knife. In a jealous rage, Charles attempts to kill his brother. Charles represents the biblical character of Cain, who kills his brother when God favors Abel's lamb over his gift of grain. Charles remains on the family's Connecticut farm and amasses a fortune of $100,000 that he leaves to Adam and Cathy.
Cyrus Trask
Cyrus is the cruel and crooked father of Adam and Charles Trask, and the man who commits the "original sin" that inspires the action of the novel. He lies about his American Civil War record to garner himself an important job in Washington D.C. Crooked in his financial dealings, Cyrus leaves his sons an inheritance of $100,000.
Mrs. Trask
The religious mother of Adam Trask, Mrs. Trask commits suicide after her husband, Cyrus, returns from the Civil War with syphilis.
Joe Valery
An escaped convict, Joe works as Kate's bodyguard and bouncer and attempts to control her. Kate comes to rely on him until she realizes that he is extorting money from her. She commits suicide after informing the sheriff of his dark past.
