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There are notable differences between many of the characters in the original Dexter novels and on Showtime's television adaptation. As can happen with books that become movies or television series, changes were made that influenced the course of the storyline. These changes include major characters' attributes, deaths (or introductions), along with miscellaneous information (such as their names, ages, addresses, relationships, etc.).
Characters in the Novels
- Dexter Morgan - Dexter's personality differs quite a bit between the novels and the TV series. In the novels, he appears even more detached from other people.
- Deborah Morgan - Debra Morgan is named "Deborah" and she learns of Dexter's secret by the end of Darkly Dreaming Dexter. She seems to accept it but, in subsequent books, feels torn between her duties as a police officer and her loyalty to Dexter. In the Showtime series, Debra walks in on Dexter as he kills Travis Marshall. When she learns that Dexter is a serial killer, she is horrified. She resolves to help Dexter stop killing by keeping a constant eye on him, which is ultimately unsuccessful. Also, in the novels, she has a son, Nicholas.
- Rita Morgan - She is murdered by Robert Chase in the novels, and by Arthur Mitchell in the TV series.
- Brian Moser - In the novels, Brian never uses the alias "Rudy Cooper" and he is known as the "Tamiami Butcher" instead of "The Ice Truck Killer". He survives the events of Darkly Dreaming Dexter, returns in Dexter is Delicious, and plays a major role in Dexter is Dead.
- Migdia LaGuerta - In the novels, Maria LaGuerta is called "Migdia" and her personality is far more harsh than on the television series. While some plot points are the same, she is stabbed to death by Brian Moser at the end of Darkly Dreaming Dexter, while her Showtime counterpart is slain at the end of Season Seven by Debra Morgan.
- Albert Doakes - He is called James in the TV series and is dead by the end of Season Two. Albert, however, stays alive but loses a lot of his body to the work of Dr. Danco.
- Lily Ann Morgan - Dexter's daughter in the novels is replaced by Harrison Morgan for the television series.
- Cody and Astor Bennett - In the TV series, there is nothing unusual about the behavior of Dexter's step-children. In the novels, though, the two show signs of sociopathy, and Dexter assists them in learning The Code of Harry.
- Lila West - She has a major role in Season Two of the television series, but has no feature role in the novels.
- Miguel Prado - He appears in Season Three of the television series, but not in the novels.
- George Washington King - He appears in Season Three as The Skinner, a character based on Dr. Danco from Dearly Devoted Dexter.
- Arthur Mitchell - He appears in Season Four as a long time serial killer who kills Dexter's wife.
- Jordan Chase - He appears in Season Five along with the Barrel Girl Gang. They may be based on the cannibals from Dexter is Delicious.
- Joey Quinn - He has a major role from Season Three forward and replaces Detective Alex Duarte of the novels.
- Stan Liddy - He has no role in the novels as the character in Season Five that is connected to Joey Quinn,
- Frank Lundy - He first appears in Season Two, and has no role in the novels. His counterpart, as a Washington hand sent to Miami to handle a serial crime case, and as the love interest of Debra, is Kyle Chutsky.
Characters in the TV Series
- Dexter Morgan - Dexter's personality differs quite a bit between the TV series and the novels. In the TV series, almost everyone who learns of his secret ultimately dies. Notable exceptions are Lumen Pierce and Hannah McKay.
- Debra Morgan - She has relationships with characters nonexistent in the novels. In the TV series, Debra Morgan eventually dies while, in the novels, Deborah remains very much alive.
- Maria LaGuerta - Instead of being called Migdia, the creators of the show decided to name her Maria. On television, she is often seen as harsh but, at times, will reveal that she has a heart despite her unrelenting political game.