Edward Prendick
Edward Prendick is the author of the manuscript that is presented as the text of The Island of Doctor Moreau. The document relates how he came to be on Moreau's island following the sinking of the ship Lady Vain. Prendick's text recounts the events of his nearly one-year stay there, including Moreau's creation of humanlike Beast People from animals and the death of Moreau and his assistant, Montgomery. When Prendick escapes from the island, his tale is disregarded as the ravings of a man too long adrift at sea.
Doctor Moreau
Doctor Moreau is a biologist who was forced to leave England after an investigative reporter publicized his animal vivisection experiments. A decade later, he is using vivisection to turn animals into human beings. He is never able to do so successfully, however, because the results of his experiments always revert back to animalism. He is eventually killed by a puma that he has partially transformed into a human.
Montgomery
Montgomery helps Edward Prendick recover from exposure after he is rescued from the dinghy of the Lady Vain, and the two form a friendship of sorts during Prendick's stay on Doctor Moreau's island. Plagued by a scandalous past and afflicted with alcoholism, Montgomery is killed by the Sayer of the Law after giving the Beast People alcohol.