Who is the monster's first victim in the novel?

William Frankenstein is the monster’s first victim in Mary Shelley’s novel Frankenstein.

William is Victor Frankenstein’s youngest brother. After learning Victor’s family name, the creature realizes that the child is connected to his creator. William reacts with fear and tries to escape, but the creature strangles him near Geneva. The murder is driven by the creature’s growing anger at Victor and at the human society that has rejected him.

The creature then places a miniature portrait of Caroline Frankenstein, Victor’s mother, in William’s clothing. This evidence causes Justine Moritz, a trusted family servant, to be accused of the crime. Although Victor suspects the creature, he remains silent, and Justine is convicted and executed. William’s death therefore begins the chain of revenge that destroys Victor’s family.

A common mix-up is confusing William with the monster’s later victims. Henry Clerval and Elizabeth Lavenza are killed afterward, while Justine is wrongly condemned rather than being the original victim. The 1818 novel presents William’s murder as the creature’s first deliberate killing of a human.