Blood slides play a major role inDexter, but the show doesn’t outright explain why the serial killer takes them as trophies, even though they go against the Code of Harry. There are two newDextershows in development: the prequel seriesDexter: Original Sinand the sequelDexter: Resurrection. Because of them, the serial killer has regained a portion of the popularity he had in thebest seasons ofDexter. Those new shows will likely answer a lot of lingering questions from the original series andDexter: New Blood, but there’s already a response to one big question: why does Dexter take blood slides as trophies?
The very practice of taking blood slides goes against the Code of Harry, the rules and guidelines Harry Morgan gave his adoptive son to keep him from being caught. The blood slides are very concrete, biological evidence that Dexter killed people, and Harry never would have approved of him having them. They even caused quite a few issues throughout the show: Doakes nearly caught Dexter because of his blood slides inDexterseason 2, and they let Debra find out he was a serial killer inDexterseason 7. Dexter’s blood slides were a major problem, but they weren’t actually a plot hole.

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Dexter Takes Blood Slides Because He’s Obsessed With Blood (Despite Going Against The Code Of Harry)
The show only gives two explanations for why Dexter collects blood slides as trophies.The more mundane of the two is that Dexter simply wanted something to remember his kills by. There are a few moments throughout the show where he goes through his box, picking out single slides and reminiscing about whose blood he has collected. This idea also fits with real life, as many known serial killers collect some kind of trophy. Even other serial killers inDextertook trophies: Miguel Prado collected rings, while the Runaway Killer preserved his victims' entire bodies.
In short, Dexter’s obsession over blood outweighed his reliance on the Code of Harry.

The more important explanation for Dexter’s blood slides is that he was obsessed with blood. Dexter was covered in his mother’s blood as a baby, and he was obsessed with it his entire life. Blood defined everything from his career to his trophies. It’s hard to say exactly what Dexter thought of blood, as he sometimes seemed to hate it, like when he first saw an Ice Truck Killer victim, and he sometimes seemed to love it, as evidenced by his job as a blood spatter analyst. In short,Dexter’s obsession over blood outweighed his reliance on the Code of Harry.
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A forgotten web-series,Dexter: Early Cuts, explains where Dexter got the idea to start taking trophies from. One of Dexter’s earliest kills, a former U.S. Marine sniper named Alex Timmons, was also an avid hunter. Since most of his victims had been innocent children in Iraq, Dexter used his taxidermy animal heads in place of photos of his victims.Then, while toying with Alex, Dexter cut his cheek and was inspired to put a drop of blood on a slide he had in his bag. He told Alex “A trophy. My first. My father wouldn’t approve, but what can I say? You inspired me.”
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What Dexter’s Blood Slides Really Mean
Dexter’s blood slides don’t just work as trophies, though, they also hold quite a bit of symbolic weight and meaning. On a basic level, the blood slides represent how Dexter is obsessed with the past, like his mother’s murder and his relationship with Harry.Dexter constantly clings to his memories, and the blood slides are a way to show that he holds onto those memories even when they jeopardize his future. There are multiple instances inDexterwhere his search for answers about his past had dire consequences, like how he spared Trinity to learn about hiding his double life and how that led to Rita’s death.
ThoughDexter: Early Cutsexplained why Dexter began taking blood slides, the upcoming showDexter: Original Sincould easily rewrite this moment and Dexter’s reasoning.

The blood slides also do quite a bit of work in givingDexterits suspense. For most of the show, they were hidden nearly in plain sight, just behind the grating of his air conditioning unit.Because they were barely hidden, Dexter’s blood slides also represent just how close he was at all times to being exposed as a serial killer. If anyone, including the several people who had searched his apartment, had found his box of slides, he would have been arrested. Dexter was living a very precarious life as a serial killer, and his blood slides were a very stark reminder of that.
His blood slides are a sign that Dexter isn’t as different from the people he kills as the Code of Harry makes him seem.

On a deeper level, Dexter’s blood slides reveal something important about his character. Taking trophies is something that regular serial killers do, and it’s evidence that Dexter was actually enjoying and reminiscing about his kills.His blood slides are a sign that Dexter isn’t as different from the people he kills as the Code of Harry makes him seem.For all his talk of “taking out society’s trash,” Dexter still kills people for his own amusement. Objectively, he’s just as much a killer as any one of the victims he kills inDexter, and the blood slides are proof of that.
Dexter
Cast
Dexter is a television series following Dexter Morgan, a blood spatter analyst for Miami Metro Police who secretly leads a dual life as a vigilante serial killer. Released in 2006, the show focuses on Dexter’s internal conflict as he hunts down criminals who elude justice within the legal system.
