Shadowhunters season 3, episode 12, “Original Sin,” unpacks the mythos of the Mark of Cain and attempts to humanize its monsters.

Bienvenue, Shadow Fam, and welcome to Paris, the second stop for Lilith’s magical flying apartment. Magic has a way of leaving a trace and luckily for Clary, she has a team of people working tirelessly to find the footprint of Lilith’s apartment.

The back half of Shadowhunters season 3 has left many of the characters surrendering to their spirals of grief and loss. Where the premiere episode, “Lost Souls” focused on the characters coming together to extend a helping hand, episode 12, “Original Sin,” shows what happens when they choose to accept it.

“Original Sin” leans heavily on the mythos of the Mark of Cain and what it means for the rest of Simon’s journey this season. It also tackles another type of mythos, one that we are just able to start unpacking — Jonathan. Is he a monster, demon, or human?

’Shadowhunters’ 3×12 review

Jonathan, Simon, and Magnus are all in the midst of an identity crisis. Magnus is living like he is dying because for the first time in his life, he kind of is. Simon is on a journey to figure out what the Mark of Cain means for his future. And Jonathan is adapting to being a fully-realized person and all the pains, urges, and decorum that entails.

While Jace and Luke take care of the pressing matter of finding out if Clary is alive, Izzy, Alec, and Clary are faced with the task of ensuring their respective counterpart does not stray too far from themselves.

Is Jonathan evil?

Monster, human, demon. At any one time in the episode, Jonathan shows signs of one or another. When he is not coddling Clary, he is threatening antiques dealers and snapping the necks of Parisian Institute members. He is a being entirely rooted in jealousy: Jealous of the life he did not get due to the absence of a true mother. Jealous of the friends he never made, the companions who never stuck around. Jealous, most of all, of how close Clary is to a family that is not blood related. His failure to comprehend and process these emotions in a human way is what will continue to feed his monstrous tendencies.

When Clary and Jonathan are at a cafe enjoying hot chocolate and croissants, Jonathan tells the tale of how he met and kidnapped Sebastian. He attempts to push the dark, twisted story into some form of light. Jonathan was jealous of his easy-going demeanor, his confidence, his kindness. By inhabiting his body, maybe he would become the man he saw sitting across from him that morning at the cafe.

Instead, he found himself faced with a scared human who was less than grateful for his daily meals. But Jonathan could not worry about the boy in the closet, not when the people at the Institute held him in such great esteem. They liked him, trusted him, and let him into their lives without a second glance.

But now the attention is on his true form. He may not have the physical burden of scars and burns, but he has something that is harder to look beyond — a stained reputation.

When Clary looks at him, she sees her captor and now a cold-blooded murderer. His threat to the antiques dealer turns out to be his unfortunate reality with Clary. Jonathan does not have her loyalty, he has her fear.

Luckily, as he whisks her away, Jace, Luke, and Alec turn up and she is able to act quickly, using herself as a voodoo doll to hurt him and escape.

And now, Clary once again is getting from others what Jonathan cannot provide her — compassion, support, and her free will. He is losing again all that he desired to gain when he took over Sebastian’s body, namely that sense of belonging.

Those final moments in the apartment reveal something worse is yet to come as his isolation propels his demonic tendencies. Without a meaningful existence, in this case taking care of and providing Clary with a sense of familial pride, what will keep him in check?

Mark of Cain

Separating fact from legend comes with the territory of being part of a world where vampires and werewolves exist. Though sometimes the commentary can lean into humor (Maia’s reaction last week after Simon says Bigfoot is real comes to mind), the more seriously the legends are taken, the better off you are. The legends, as they say, are true.

For Simon, this week means finding Cain. Hidden away in a Sirius Black-level of dishevelment, Cain and Simon find that in each other’s company, their shared marks do not inflict harm, but rather respond the way magnets of the same polarity might. Simon does not exactly see a foe in Cain, but he does see a vivid reflection of himself and what his life might become if he heads further down his path of complete isolation.

Cain reveals that Lilith’s influence over history is far greater than just tormenting the likes of the Institute over the past several months. Lilith, scorned by Adam, never quite forgave Adam betraying her, and she marked Cain as her pawn to carry out Abel’s murder. Unbeknownst to Cain, Lilith had made him into a vampire and thus after crushing his head with a rock, he drank Abel’s blood.

Abel’s heavenly blood is what allowed him to become a Daylighter, but his mark and the danger it caused sent him into isolation. He shares this story with Simon in an attempt to uncover the struggles he faced for centuries, but also as a way to plant some seed of bravery in him.

Simon, seeing the haggard, tired immortal takes the offering of the stone to the Seelie Queen, ready to face the pain of removing the Mark of Cain. But, of course, the Seelie Queen keeps the full details of the operation under wraps, leaving Simon close to death at the end of the ritual.

Isabelle allows Simon a few drops of her blood to bring him back from the edge, but her loyalty to saving her friend pushes her to face a difficult decision — allow him to drink from her and make a full recovery or let him die. Seeing her struggle, especially as she has not too long ago gotten clean of vampire venom, pushes Simon to talk her out of it.

But unlike with Raphael, Izzy is looking in this moment at a chance to save a life. She is bravely putting herself at risk, but I believe she trusts that when this is over, she will have the support she needs to recover. And as she slumps over, we see Simon rise up, catching her head on his.

Stop and smell the Slovaki vendor

Do you miss my cat eyes? Phew. Alec and Magnus certainly know how to capture our attention. But for every bit of charged eye contact during that training scene, there is a certain level of strained connection between the two. As Magnus begins to operate in triple time, Alec is struggling to keep pace.

For Alec, the future is impossibly long. For Magnus, it is as if it will be over if he blinks his eye. And this push and pull between their desires is going to take some open and honest communication. Magnus is quick to cut off Alec in this episode, but it is out of fear of missing something great.

What could be greater than taking a few moments to sit with the love of your life in silence? In 25 years, Magnus might not remember what the popup art gallery showcased, but he will remember the way Alec’s eyes crinkle when he laughs. Soaking up those memories and taking a breath is going to help Magnus come to terms with his new reality and allow Alec time to figure out what he can do to help his partner.

It’s evident that Magnus has a lot to offer in the present moment. He is able to identify a way to trace Clary and he is no chump when it comes to hand-to-hand combat. (Side note: Thank the Angel this production team tapped into Harry Shum Jr.’s incredible talents for the training segment. His movements are so fluid and beautiful, it almost makes me miss Glee. Almost.)

I look forward to seeing how this struggle continues to affect their relationship and how it will help inform their strengths and come to terms with their weaknesses. I believe they will be stronger having gone through and learned from this together.

In the age of finding the next Insta-worthy moment, let Alec’s words be a lesson to us all: “The thing about moments is you’ll miss them if you’re always running around looking for the next one.”

Stray observations

Shadowhunters season 3, episode 13, “Beati Bellicosi,” airs Monday, March 11 at 8:00 p.m. ET on Freeform.