I have wanted . . . to commit a murder myself. I recognized this as the desire of the artist to express himself! . . . But—incongruous as it may seem to some—I was restrained and hampered by my innate sense of justice. The innocent must not suffer.
This quotation is taken from Judge Wargrave’s written confession, which appears in the epilogue to the novel. In this passage, Wargrave explains how he hatched the idea of bringing a group of unpunished murderers to Indian Island and killing them off. Killing people who committed crimes unpunishable under the law satisfied both his desire to murder and his desire to mete out justice for wrongdoing.
This combination of murderous zeal and obsession with justice leaves Wargrave occupying a paradoxical place in the novel. He is both the murderer and the detective in this mystery, both the agent of death and the agent of justice. He is not a likable character, and our sympathies lie with the other people on the island, even with the ones clearly guilty of murder. But in a sense, Wargrave does act according to just principles, killing those, including himself, who are themselves responsible for the deaths of others.