Summary

• Shadowhunters successfully adapted the main storylines from Cassandra Clare's novels, but there were some storylines that were left out.
• Missed storylines include Jonathan and the Seelie Queen's relationship, Max Lightwood's death, Jace's Herondale connections, the Endarkened Shadowhunters, and the Blackthorns' role.
• The series did not fully develop Simon and Izzy's relationship, and Clary and Jace did not get their happy ending like in the books.

Trying to adapt six long novels into three seasons of television is most certainly a challenge, and as a result, it's easy for a television series to miss certain book storylines, just as Shadowhunters did with its own source material, "The Mortal Instruments." Although Shadowhunters made an effort to include all the epic highs and lows of Cassandra Clare's young adult novels, there are still some storylines that fans will never see since the series was canceled. While some of these storylines may seem small, they actually significantly expand the story, and often, lead the way to Clare's other Shadowhunter novels.

First and foremost, Shadowhunters mostly succeeded at adapting Cassandra Clare's story to the screen. Although a film adaptation entitled The Mortal Instruments: City of Bones was released in 2013, the move franchise never took off after that first movie, leaving Shadowhunters to be the leader of adapting the remainder of the "Mortal Instruments" books. Ultimately, the show brought all the biggest storylines to life including Clary and Jace's complex relationship, the rise of Valentine and Jonathan, and the climactic war between the Shadowhunters and Jonathan's demonic forces. However, there were some storylines that never saw the spotlight they deserved, and as a result, may never be adapted to screen.

7 Jonathan And The Seelie Queen's Relationship

Though Shadowhunters saw Jonathan's descent into evil come fairly quickly, spurred on after he slept with and killed the Seelie Queen, this progression was much slower and more detailed in the books. Jonathan and the Seelie Queen had a relationship that ran much deeper and longer than it appeared on Shadowhunters, and without this development, Jonathan's character lacked important details. In fact, showrunners cite Jonathan and the Seelie Queen's relationship as a Shadowhunters plot point that they would have expanded on if given another season, according to Entertainment Weekly. With more time, Shadowhunters could have shown the complicated sexual and strategic connection between the characters.

6 Max Lightwood's Death And Its Consequences

In Shadowhunters, Alec and Isabelle's younger brother Max survives the Dark War and moves to the L.A. Institute with his mother, however, the character receives a much more tragic ending in the books, that is actually quite important for the rest of the characters. In Cassandra Clare's third "Mortal Instruments" book, Max is killed by Jonathan, otherwise known as Sebastian. While keeping him alive in Shadowhunters may seem like an extra kindness, it actually affects much of the Lightwood family's character development.

First and foremost, Max's death tears the Lightwood family apart in a sense. Though Alec's relationship with Magnus puts a strain on his connection with his father, Max's murder is a breaking point for the already hurt family. Though, it also helps in some ways. Max's death helps the rest of the Shadowhunters figure out Sebastian's true identity, and also, it proves how high the stakes are in this war. Isabelle, who previously had an uncaring, party girl attitude, strengthens due to her brother's death. Because Max lived in Shadowhunters, all of this Lightwood family drama will never get the chance to be explored.

5 Jace's Herondale Connections In Shadowhunters

A major revelation in both "The Mortal Instruments" and Shadowhunters is that Jace is not a Wayland or a Morgenstern, but is a Herondale. Mainly, this fact is important because it makes it clear that Jace and Clary are not siblings, and so their romance can continue. However, in the context of "The Mortal Instruments" books, the name Herondale has extra significance. This importance continuously appears throughout the series, especially with the introduction of new characters with strong connections to Jace and his family name including Brother Zachariah and Emma Carstairs.

Though Brother Zachariah makes brief appearances in Shadowhunters, his character is much more important in the books. Not only does he have knowledge and powers that can help the characters, but he also has a direct connection to Jace and his family. In particular, Zachariah used to be the best friend of Jace's ancestor, Will Herondale. This fact is especially important because it makes up an entire different series that Cassandra Clare wrote entitled "The Infernal Devices." In this way, without delving into Brother Zachariah's character, Shadowhunters avoided the possibility of an "Infernal Devices" spinoff, or at the very least, references for fans of the series.

4 The Endarkened Shadowhunters

One factor that made Jonathan's reign of terror worse was the use of Endarkened Shadowhunters, which were not included in Shadowhunters. The Endarkened were Shadowhunters who became evil after drinking a mix of blood from the demon Lilith and Jonathan from the Infernal Cup. For the most part, these Shadowhunters were not willing to become Endarkened, but instead, were forced to drink the mixture and become evil. As a result, the Endarkened were not only fierce opponents for the Shadowhunters, but were also a tragic example of Jonathan's evil. Without them, Shadowhunters avoids the dark moments wherein Shadowhunters had to fight their own loved ones who had become Endarkened.

3 The Blackthorns And The L.A. Institute

Another Shadowhunter family that Cassandra Clare explores in a spinoff book series is the Blackthorns in "The Last Hours." In Shadowhunters, audiences get a hint of Blackthorns through Helen, who helps the Shadowhunters characters figure out supernatural problems and has a relationship with fellow shadowhunter, Aline. However, Helen's story goes much deeper than just being a helper during the Dark War. In the books, Helen suffers a major tragedy when her home, the L.A. Institute, is attacked by Jonathan, and everyone inside is killed besides her younger siblings. Furthermore, because of Helen's faerie blood, she is exiled for a time during the book series.

Similar to Brother Zachariah's lack of importance in the Shadowhunters episodes, Helen could have played a role in ushering in Cassandra Clare's other Shadowhunter stories. The Blackthorn family is a particularly interesting sect of shadowhunter history, and the role they play in the Dark War is especially important. Shadowhunters missed out on some very engaging subplots by ignoring Helen and Aline's romance, Helen's family tragedy, and the role the Blackthorns played in the fight against Jonathan, particularly the Blackthorn patriarch becoming Endarkened.

2 Simon And Izzy's Shadowhunters Relationship

Although Simon and Izzy end up together at the end of Shadowhunters, their relationship didn't get the development it deserved. Though the series held off on their romance, pairing each of them with different people in the earlier seasons, this separation wasn't the only thing holding them back from their book romance. In "The Mortal Instruments," Simon and Izzy suffer from the fact that, early on, Isabelle believes herself to be cooler than Simon, and is hesitant to start a real relationship with him. The way the pair navigate their differences and put their love first deepens the romance, and without it, their Shadowhunters relationship seems rushed.

1 Jace And Clary Ending Up Together For Good

The most upsetting storyline that Shadowhunters will never be able to bring on-screen is Clary and Jace actually ending up together. At the end of Shadowhunters, Clary is deruned and, as a result, loses her memories of the Shadow world. The final moments of the series see Jace watching Clary, looking for a sign that she might . On the other hand, in "The Mortal Instruments," Clary never loses her memory, and she and Jace live happily ever after. This is undoubtedly a more satisfying conclusion to their romance, and it's a shame that no proper Shadowhunters adaptation has been able to give the couple their happy ending just yet.