Hank Morgan – The Boss
The protagonist and narrator. Hank is smart, resourceful, and genuinely appalled by medieval injustice—but also arrogant, paternalistic, and addicted to being the smartest person in the room. His arc ends in catastrophe partly because he can't separate helping people from controlling them.
King Arthur
Arthur starts as a naive, ceremonial king with no real understanding of how his kingdom works. The disguise journey cracks him open—he shows real courage and genuine horror at what he witnesses. Twain makes him more sympathetic than Hank by the end, even if he remains limited.
Merlin
The court magician and Hank's main rival. Merlin is a fraud and a schemer, but he's patient and politically savvy. He survives by attaching himself to the Church's power. His final curse on Hank is the novel's darkest joke: the con artist beats the engineer.
Sandy (Alisande)
A noblewoman Hank meets on a quest. She talks constantly and takes everything literally, which drives Hank crazy at first. She becomes his wife and the mother of his daughter, and Hank's love for her is one of the few genuinely warm things in the novel. Her absence during the final crisis is part of what undoes him.
Clarence
A young page Hank befriends early in his time at Camelot. Clarence becomes Hank's most trusted lieutenant, helps run the secret modernization project, and leads the boys in the final battle. He is loyal, capable, and one of the few characters who genuinely absorbs Hank's ideas.