SPOILER WARNING: Plot details follow. Caution is advised!
The Battle of the Burren was when everything went wrong.

Livvy to Julian and Emma, Queen of Air and Darkness

Thule is one of many worlds—an alternate dimension of the world known.[1]


Thule is a world where, due to the blight, no magic except for those of the demonic nature works. Due to the absence of angelic magic, the magic and tools—seraph blades, runes and steles—that made Shadowhunters were rendered useless. Warlocks no longer exist, faeries were walled off in their land, and the remaining population—mundanes, former Shadowhunters, vampires, werewolves—was, for a time, split between those sworn to Sebastian Morgenstern and those in rebellion of his rule.

The sky in Thule was also affected by the blight. The sun and the moon cast only a dim, reddish light on the land. Fog was very thick, giving very little visibility outdoors without light and even muffles sounds; it makes a person's eyes and throat sting and burn. Rain in Thule is said to be worse than fog.[1]


Battle of the Burren

In 2007, when Sebastian Morgenstern summoned Lilith for her blood, she had assistance from another demon that allowed her to regain her strength much faster. During the Battle of the Burren, when Clary came at Jace with Glorious in order to separate his tie to Sebastian, Lilith cast the sword into Hell and killed Clary. Helen Blackthorn, Aline Penhallow, Magnus Bane, Isabelle and Alec Lightwood, and the others barely escaped, and Jace remained in Sebastian's control.

Sebastian later killed Lilith, claiming it was in revenge for Clary's death, though most believed he only said this for Jace's benefit to keep him subservient.[1] Sebastian later went after his real mother, Jocelyn, and killed Luke when he tried to protect her. Clary's best friend Simon also mysteriously disappeared.[2]

Fall of Idris

Clary's death became a turning point for the war. Sebastian joined forces with the faeries and stormed the Institutes and eventually Alicante. Sebastian and his forces proved too powerful for the Shadowhunters, and soon their only option had become escape. A group of warlocks opened a Portal to a shelter set up by Magnus and Catarina Loss in New York but only let children below fifteen through. Aline, Helen and Mark were left in the Accords Hall, separated from their younger siblings, until Mark was taken by the fey.

Helen and Aline continued fighting in Idris with the others. During this time, their lands, beginning with the Brocelind Forest, became affected with the blight—doorways for demons, allowing the demons to flood into Idris. Demons, faeries, and the Endarkened drove the Shadowhunters out of Alicante, and soon, the country fell. Sebastian's demons ravaged what was left of Idris with demonic poisons and shattered the demon towers.

At the final battle in Idris, Isabelle took up the Mortal Sword against Sebastian. By that point, the invulnerability granted to him by Lilith had grown so powerful that nothing in Thule could kill him, and the Sword failed to even nick him; he then killed Isabelle.

Fight for survival

The blight began to spread to the rest of the world, and demons flooded the streets and slaughtered humans, no longer able to be hidden from the mundanes. Thus began the fall of Manhattan. The shelter in New York fell only months after the war. The blight also made the warlocks ill; others died, while some turned into demons, more quickly affecting those older and powerful warlocks, or those who used magic more often. By the time the cure—the water of Lake Lyn—was discovered, Sebastian already had the lake surrounded with demons.

When Magnus realized that he was turning into a demon, he asked Alec to kill him. Alec did as asked then killed himself to avoid being captured and forced to give up information on the resistance. Catarina also fled to avoid hurting anyone. With the shelter gone, the children went their own ways. Emma and the Blackthorns stuck together, and at one point, Emma and Julian began dating.

Catarina had arranged for trains to take Shadowhunter and Downworlder children across the country due to the belief that the demons were spreading east to west, and that California was still clear. When the children arrived at a station, with the last train about to leave, a huge group of Dark Shadowhunters arrived. Julian forced the children onto the trains and, with Emma, held back the Endarkened as the train departed the station. The two were promptly turned into Endarkened.

Meanwhile, the faeries lost many warriors during the war, and the Seelie Queen herself was killed. As their reward, Sebastian granted them the isolation from the human world that they desired, closing off entrances to their land. The Unseelie King united the two Courts and ruled over them all, naming his son Prince Erec as his heir. Nonetheless, faeries are still free to come and go as they pleased, and punishment faces any—mundanes and Endarkened alike—who threaten them.

Werewolf packs were scattered, leaving the remaining lone wolves to fend for themselves by either submitting to Sebastian or joining the resistance. Vampires fared mostly well as demons did not want to eat them as much as other beings, and while some joined the resistance, some joined cults that worshipped Sebastian, believing that he would bring them to a world with more victims if they run out of humans in Thule.

When Sebastian and the blight he'd unleashed had spread far enough, everything seraphic that the Shadowhunters had access to lost its power—seraph blades and their runes. At one point, supposedly in response to how dark and demonic the world had gotten, every parabatai pair became true Nephilim—giants burning with heavenly fire that wreaked havoc, destroying cities and taking countless lives. It took thousands of demons, released by Sebastian, to defeat them, resulting in even more casualties.[1]


Around two years after the war, two people from another dimension found their way to Thule: Annabel Blackthorn and Ash Morgenstern, the son of Sebastian and the Seelie Queen in the other dimension. Sebastian took Ash under his wing and accepted Annabel into his fold as one of his torturers.

Around five years later, two more outsiders from Ash's world arrived: Emma Carstairs and Julian Blackthorn. These two helped the Bradbury bunch—a group of rebels in Los Angeles—find the Last Warlock, Tessa Gray, who then opened the Silent City for them, intending to secure the Mortal Instruments. Sebastian's army had been lying in wait and ambushed them when the Silent City was reopened, leading to a confrontation. In the hands of Emma, the Mortal Sword was able to kill Sebastian, being from another world outside of the invulnerability to Thule warriors granted to him by Lilith. Sebastian's death also resulted in the destruction of his Endarkened army. Emma and Julian then left Thule, bringing the Mortal Sword with them and leaving the Mortal Cup with the rebels in hopes of bringing back Nephilim in Thule.[1]

Known residents

Missing/Fates unknown:


Warlocks (turned into demons):

Endarkened (destroyed):


  • Clary's absence was the main difference that caused the butterfly effect towards this world's downfall. Without Sebastian's desire to make deals with the Clave in exchange for Clary, and without her rune and Jace's heavenly fire that eventually killed Sebastian, the world became doomed to fall at Sebastian's feet.
  • The fate of this world's Simon Lewis may be revealed in a future installment.[3][2]
  • Apparently, Julian whispered the name of the Unseelie King to Livia in her ear before he left Thule,[4] which would allow her to hold power over the king and might help in their efforts in Thule.
  • The demon that helped Lilith regain her strength at the Burren is a powerful, dangerous one that is set to be revisited in a future installment. Though its identity has yet to be revealed, Cassandra Clare has shared that it was a demon associated with Lilith in mythology.[5]
  • In Chain of Gold when Cordelia Carstairs passes through the Portal into Belphegor's realm, she sees a glimpse of Thule along with other dimensions.[6][7]


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