Warning! This article contains SPOILERS for Dexter: Original Sin episode 1 & Dexter: New Blood.The premiere of Dexter Morgan killed at least 144 people and became the infamous Bay Harbor Butcher, he began with a single victim. While the original Dexter show did depict his first kill, Dexter: Original Sin has gone into much deeper detail on the subject, and it's given viewers an even better look into the serial killer's last days in college. It also changed a few things about the original show and Dexter: New Blood, and there were some major reveals.

Dexter wasn't the only person in Original Sin whose life before the original show is being examined. From Harry (Christian Slater) and Debra Morgan (Molly Brown) to the officers of Miami Metro, Original Sin is adding new layers to some of the original show's earliest characters. It also added a few new players into the mix, notably Sarah Michelle Gellar's Tanya Martin, and everyone had some major reveals in the premiere. These 10 moments were the biggest, however, and they'll likely be important to the future of Dexter: Original Sin.

10 Dexter Survived Harrison Shooting Him In Dexter: New Blood

Dexter: Original Sin Is Dexter's Life Flashing Before His Eyes On The Operating Table

As soon as Dexter: Original Sin began, it started doling out massive reveals for the franchise. At the end of Dexter: New Blood, Dexter seemingly died in the sequel series. Harrison (Jack Alcott), Dexter's son, shot him in the chest with a rifle, and it looked like he bled out in the snow. Original Sin, however, immediately set the record straight and established that Dexter hadn't died when Harrison shot him; Angela Bishop (Julia Jones) took him to the hospital and surgeons worked to keep him alive. All of Original Sin is framed as Dexter's life flashing before his eyes on the operating table.

Dexter surviving New Blood's ending is surprising in its own right, but it also comes as a shock for another Dexter show. After Original Sin, another show, Dexter: Resurrection, is on the horizon, and it's set to take place after New Blood. Many people thought that Resurrection, not Original Sin, would explain how Dexter could survive the gunshot, yet that explanation came much earlier than anticipated. It also means that Original Sin and Resurrection are much more closely linked than previously thought, as they essentially take place at the same time.

9 Angel Batista & Vince Masuka Worked With Harry Morgan

Angel & Vince Seem Like Major Characters In Dexter's Origin Story

Two of Dexter's best friends in the original series - Angel Batista, now played by James Martinez, and Vince Masuka, now played by Alex Shimizu - ed the cast of Dexter: Original Sin in the premiere episode. Interestingly, both Angel and Masuka worked directly under Harry Morgan, long before Dexter began working there as a forensic technician. It seems that in Original Sin, both Batista and Masuka are still rookies, as Batista works under Harry and Masuka works under Tanya Martin (Sarah Michelle Gellar).

It should be interesting to see how Dexter: Original Sin depicts the beginnings of Dexter's friendship with Batista and Masuka. Dexter almost always asserted that they weren't actually his friends, and he's also a fairly strange person in Original Sin. The prequel show likely has some kind of special event or plot development in motion to get Batista and Masuka to like Dexter and start hanging out with him outside of work, but it's not clear what that could be yet.

8 Harry's Original Plan Was To Let Dexter Get His Bloodlust Out As A Doctor

Cutting Into A Cadaver Wasn't Enough To Satisfy Dexter's Bloodlust

In the original series, a few characters found it odd that Dexter was such a great candidate for medical school, yet he went into forensic science instead. Dexter: Original Sin has finally shown exactly why Dexter took that path, and it was unexpectedly a bit more involved than it seems. Harry had originally wanted Dexter to become a doctor so that he could cut into people and satisfy his bloodlust by helping people, not hurting them. However, when Dexter cut into the cadaver and didn't see any blood, he doubted that a life as a doctor would ever be able to satisfy him.

When Dexter cut into the cadaver and didn't see any blood, he doubted that a life as a doctor would ever be able to satisfy him.

It was only after Dexter saw Masuka's booth at the career fair that he decided to go into forensics and be closer to crime scenes and blood. Dexter was enchanted by the crime scene pictures, and he eventually decided to take an internship at Miami Metro. It's not clear how this changes the plan that Harry and Dr. Vogel created in the original series, or why Harry agreed to let Dexter give up on becoming a doctor.

7 Dexter Saved Deb From A Rapist At A Frat Party

Dexter Would Have Killed The Rapist If Someone Hadn't Shoved Him

A week before Dexter's graduation, Harry ordered Deb (Molly Brown) to take him to a fraternity party they had both heard of so that he could mingle with people his own age. At the party, Deb got extremely drunk, and her friend got Dexter to intervene after a man took her into his room while Deb was unconscious. Dexter fought the rapist after seeing that he had his pants down, and he would have grabbed a knife and killed him if another man hadn't tackled him. That got Deb and Dexter kicked out of the party, however, and Deb was initially mad at Dexter for embarrassing her.

Throughout the premiere of Dexter: Original Sin, Deb had thought of Dexter as a dork and an embarrassment. After she realized that he saved her from being raped, however, their relationship started to improve, and Deb didn't seem as hostile to her older brother. It seems like the frat party may be the foundation of the extremely close and loving relationship Deb and Dexter had in the original series, and that they might continue to grow closer as Original Sin continues.

6 Harry & Doris Morgan Had A Son Before Dexter Who Drowned On Harry's Watch

The First Morgan Son's Death Was Likely The Reason Harry Adopted Dexter

In a massive change to the Morgan family's makeup, Dexter: Original Sin revealed that Deb wasn't the only biological child of Harry and Doris Morgan. Years before they adopted Dexter, Harry and Doris had a son, presumably named Harry Jr., who died while Harry was watching him. In a flashback, Harry was watching football and drinking beer when he realized Junior wasn't there, and when he found his son, Junior was at the bottom of their swimming pool. Despite giving him R and calling an ambulance, Junior died.

It's possible that Harry was trying to replace Junior with Dexter, and trying to save another son since he couldn't save Junior.

While it doesn't outright confirm it, Original Sin seems to be implying that Junior's death was a big reason Harry adopted Dexter at all. The original series explained that Harry took Dexter in when he found him in a pool of his mother's blood in the shipping container, and Dexter was about the same age at the time as Junior was when he died. It's possible that Harry was trying to replace Junior with Dexter, and trying to save another son since he couldn't save Junior. Whether that's actually the case or not, however, remains to be seen.

5 Harry Morgan Had A Heart Attack But Recovered

Nurse Mary Tried To Poison Harry, But He Recovered After Dexter Killed Her

While on one of their hunting trips, Dexter told Harry about the altercation at Deb's party and how he almost killed her rapist. That was enough to stress Harry out and get his blood pressure up, and he had a heart attack in the woods. Dexter carried him to safety and got him to the hospital, but that wasn't the end of Harry's problems. The nurse in charge of Harry's recovery, Nurse Mary, was actually a serial killer who regularly poisoned her patients. She had gone unnoticed for years, and she had picked Harry as her next victim.

Because of Nurse Mary's poison, Harry started to get worse in the hospital. He got so unhealthy that he actually gave Dexter permission to kill Nurse Mary just to keep himself alive. After Dexter did the deed, Harry's condition immediately improved, and he ended up making a full recovery and going back to work at Miami Metro. The cost of Harry's recovery, however, was letting Dexter kill his first victim.

4 Nurse Mary Was Still Dexter's First Kill - But He Was Much More Involved

Dexter Manipulated Harry Into Letting Him Kill Nurse Mary

In the original show, Nurse Mary was also Dexter's first victim, but Original Sin slightly modified the way he killed her. Harry still gave Dexter permission to kill Mary, but it was only after Dexter had done his usual vetting process and determined that she was definitely a killer. Dexter also went to some lengths to manipulate Harry and make him think that letting him kill Mary was his own idea, which recontextualizes the start of Harry's strange mentorship of Dexter. Once he actually got Mary on the kill table, however, it played out very similarly to the original show's depiction of the moment.

Since Mary was the first person Dexter ever killed, his execution wasn't very good. He had to physically restrain Mary instead of simply injecting the tranquilizer into her neck, and he also had some trouble setting up his plastic sheets. Original Sin also gave Mary a lot more characterization than the original show did, and it revealed that she looked down on the people she killed for throwing their lives away. The show expanded Dexter's first kill very well, but it also expanded what he did after his first kill in a gruesome and interesting way.

3 Dexter Used To Dispose Of Bodies By Feeding Them To Alligators In The Everglades

Before He Had His Own Boat, Dexter Dumped Bodies In The Everglades

In the original series, Dexter was known for chopping up his victims, placing their body parts in trash bags, and dumping them off the side of his boat into the Atlantic Ocean. In Original Sin, however, Dexter didn't have access to a boat, and he had to get more creative with how he discarded Mary's body. Instead of dumping her in the ocean, Dexter dumped Mary's carcass in the Everglades and let a pack of alligators devour her body. It was rather inventive for a person who didn't have a boat, but Original Sin is likely going to give Dexter a reason to switch to burials at sea.

Another difference in Dexter's kill ritual in Original Sin from the original series is the fact that he took a trophy off Mary. After he dumped her body, Dexter revealed he had one of Mary's earrings to her by, and Michael C. Hall's voice-over ominously declared that he would regret doing so. That was a bit of a retcon as well, as the original series only ever said that Dexter started taking blood slides as trophies of his victims, not earrings.

2 Dexter Missed Deb's Volleyball Game To Kill Nurse Mary

Deb Still Went To Dexter's Graduation Even Though She Was Mad At Him

Before he got permission to kill Nurse Mary, Dexter had promised that he would attend Deb's volleyball game since Harry couldn't. However, since he was occupied with butchering and disposing of Mary's body, Dexter missed Debra's game entirely. Deb was, understandably, mad at Dexter for not carrying through on his promise, but she still ended up attending his graduation. As she told Dexter, family is more important than her grudge, and it seems like another sign that she's going to grow closer to her older brother.

It seems that Dexter has some lessons to learn from his early days as a killer before whatever Dexter: Resurrection has in store for him.

The moment when Dexter saw Debra at his graduation ceremony also had one interesting detail that reveals a bit about what Original Sin means for the rest of the franchise. Dexter's voice-over, which is supposed to be the older Dexter from New Blood looking back on his memories, realized that his life has always been about his family, even when he was a young adult. It seems that Dexter has some lessons to learn from his early days as a killer before whatever Dexter: Resurrection has in store for him.

1 Dexter Graduated & Took An Internship At Miami Metro Under Tanya Martin

Sarah Michelle Gellar's Character Is Vince & Dexter's Boss

At the end of Dexter: Original Sin, Dexter started his first day as a forensic intern at Miami Metro. Harry was initially skeptical of Dexter working at the police office, but as Dexter's voice-over explained, it was time for a change. He wasn't satisfied with being a doctor anymore, especially after getting to kill Nurse Mary, and the only way he could satisfy his bloodlust was by working with murder scenes. It also means he'll be in the belly of the beast, however, and the younger Dexter isn't good at hiding his dark enger yet.

If someone does catch wind of Dexter's dark enger, it could easily be his boss, Tanya. She wasn't even mentioned in the original show, and it seems like Dexter is going to take her spot at Miami Metro permanently. It's not clear exactly how Original Sin will get rid of Tanya, whether she'll be revealed as a killer for Dexter to take out or if she leaves by some other means remains to be seen. All in all, however, Dexter: Original Sin is off to a very good start.