Harrison Morgan's fate in the upcoming Dexter reboot doesn't seem that bright, and the titular killer's forgotten sidekick might underline the likelihood of his son's tragedy. The Showtime series had an eight-season run that followed the life and inner thoughts of Dexter Morgan (Michael C. Hall), who is a serial killer who satisfied his urges by targeting other murderers in a vigilante-style nightlife. His adoptive father, Harry, helped him recognize and channel his compulsion to kill from a young age.
Dexter faithfully carried that moral code with him into his adult life, semi-justifying his behavior to himself. Once he had his own son, Harrison, the narrative in his head became much more complicated. After all, if he had an insatiable blood lust, which Dexter referred to as his "Dark Passenger," the possibility of passing on that trait via genetics or inadvertent modeling was likely.
In season 5, Dexter met a woman named Lumen Pierce (Julia Stiles). Lumen had been brutally raped and tortured by a group of men called the Barrel Girl Gang and hellbent on seeking revenge for what she'd endured, Dexter mentored her in his personal brand of homicidality and Harry's code. Despite taking the plunge of killing, she didn't feel a need to continue on the path long-term. Once the last member of the gang was killed off, she moved on and left Dexter, despite their relationship. Though it was sad she departed the series, Lumen proved a murderer within the show's universe could stop once their need for vengeance is sated. That's a good thing, but it doesn't put the odds of that happening in Harrison's favor. The Trinity Killer (John Lithgow), who was responsible for his mother's demise, is already dead. There's no vengeance to be had.
However, Harrison could always weaponize his turmoil toward Dexter, since he set the stage for much of his son's pain. No matter what, Harrison's mother is gone. He grew up without her and that's a loss that will never truly fade. The fact he can't even seek revenge on Trinity leaves him with two options; heal and move on or follow in his father's violent footsteps (possibly going after him while doing so). After spending part of his childhood without either parent and discovering the dark truth about serial killer father Dexter abandoning him - like a recent reboot teaser implies he will - Harrison's chances at a healthy, happy life continually dwindle.
Once the Dexter revival premieres, everyone's favorite serial killer will officially be back to his old ways. This is an exciting prospect for fans, especially those who were disappointed by the original series finale. But the fact that Dexter clearly isn't able to let go of his Dark Passenger or create a new life is inherently tragic. Judging by past events and indicators about the show's future, that same darkness seems likely to stick around.