The Cohort's parley was a public conference staged by the Cohort that turned into a battle after it was interrupted and foiled by the Shadowhunters and Downworlders of Livia's Watch. It took place in September 2012 on the Imperishable Fields in Idris.
In an attempt to display their power and command respect from their respective people, Horace Dearborn and the new King of the Unseelie Court Oban secretly agreed to stage a parley where both parties would appear to get what they want from the other and reach an agreement which their predecessors were unable to accomplish.
The agreed upon outcome was meant to benefit the leaders, and apparently the people, of both sides: the Cold Peace would end with the surrender and admission of the Unseelie Court to their faults. Following that, both sides would be free of future interference among each other, with the faeries being banned from Idris and all Shadowhunters banned from Faerie, with their entrances to be sealed off with wards. Meanwhile, the Unseelie Court would have Shadowhunters on their side against the Seelie Court and other Downworlders.
When it was believed that Clary Fairchild and Jace Herondale had gone to Thule and were as good as dead, Dearborn sent out a message to all Institute heads to inform them of the pair's deaths in the hands of faeries, causing outrage as they'd expected. Dearborn announced a declaration of war against faeries and shared that the Council would be reaching out to the Unseelie Court to seek parley and reparations. With the declaration of war, all Nephilim were instructed to return to Idris.
The truth that the Cohort and the Unseelie Court wasn't aware of was that Clary and Jace weren't dead. Armed with this advantageous secret and an idea of what Dearborn hoped to accomplish with the parley, Julian Blackthorn called for a war council at the Los Angeles Institute, forming the resistance known as Livia's Watch.
Anticipating the possibility of a spy, Julian secretly held two meetings: one with all Shadowhunters and Downworlders who apparently didn't agree with Dearborn and Oban, and the second with only Downworlders and the most-trusted Shadowhunters. Though the Silent Brothers initially decided to stay neutral, the Iron Sisters sent a representative in support of their cause against the Cohort. Julian shared parts of his plan during the first meeting, allowing the spy to hear what he wanted Dearborn to hear, but shared the whole plan only in the second meeting. Because of this, Dearborn did not anticipate the arrival of the Downworlders on the field.
Under the eye of every Shadowhunter, Julian and his friends marched onto the Fields and interrupted the Cohort's parley. Julian told all of the pretense behind the scene before them: how Horace knew the former Unseelie King was spreading the blight that rendered nephilim useless and was sickening and killing warlocks and allowed it; how he had long been allied with Oban and had a hand in getting him crowned; how Horace sent Dane Larkspear into Faerie to murder him and Emma; the truth of what happened at the Scholomance with Samantha Larkspear; and how he used all this to trick the Council into adopting his bigotry and managed to force Downworlders out of Brocelind Forest. Julian also had Manuel Villalobos, under the influence of the Mortal Sword, confess to the plan and his attempt to kill Clary and Jace (after they learned they were still alive) under Horace's orders.
After a little more prodding, Horace also admitted to having done it all, claiming it was an "honorable" attempt at saving the Clave from themselves. Alec then tried to end the parley by telling the Unseelie army to leave and that Horace was no longer able to negotiate as his loyalty was in question. However, they refused to listen as Alec had no authority to send them away.
Nene interjected soon after the refusal and told Oban that the fey did not accept him as their king to be able to negotiate either. That they viewed Kieran as their rightful ruler, as he is the one who killed the previous monarch. Kieran challenged Oban to a duel for the throne which caused him to become enraged and fire an arrow from his bow, missing Kieran and killing Julie Beauvale. Alec began firing arrows at Oban and his Redcaps, the Downworlders surrounding the area charged along with the Cohort and battle ensued.
After a minor altercation at the gate, the Shadowhunters that had been in Alicante watching the Projection, stormed the battlefield. They joined their fellow Shadowhunters and Downworlders in fighting the Unseelie army and the Cohort. While they mainly used lethal force against the Unseelie faeries, they tried not to kill the Cohort. Regardless of the Cohort's attempts to kill them, they did their best to either render them unconscious or lock them up in the Malachi Configuration.
In the middle of the battle, the Riders of Mannan appeared to kill Kit Herondale as they revealed he was the descendant of the First Heir. However Kit had a surge of magic flow through him and he managed to lift the Riders into the air and drop them from a great height into the center of the melee. Now with the Riders involved in the massive battle, even more chaos ensued as bodies fell.
Soon after the Riders got involved, the parabatai curse consumed Emma and Julian and they rose up in heavenly fire as True Nephilim. The battle around them stopped as all looked on with awe until Julian picked up Horace and snapped him in half, letting his body fall with a thud. Then awe turned to horror: Downworlders began to flee to safety, some Shadowhunters did as well, though most tried to form a barricade between the giants and the walls of Alicante (to protect those within the city). It seemed impossible to get through to them and make them stop as the will of Heaven drove them forward. Eventually the Blackthorns gathered, along with their friends, and were able to bring them back to themselves; officially ending the battle.
In chronological order:
- Julie Beauvale
- Vivianne Penhallow
- Timothy Rockford
- Horace Dearborn
- Martin Gladstone
- Riders of Mannan
In the days after the battle, the 50-60 odd members of the Cohort were imprisoned and questioned about their crimes with the Mortal Sword. On the 4th day after the battle, the Clave held a meeting to dull out their sentencing; as well as elect a new Inquisitor and Consul. The Cohort were given mercy and were to be split up among Institutes to rehabilitate them and give them a chance to redeem themselves and rejoin the Clave.
In a surprising turn of events, the Cohort prisoners managed to get a hold of knives and held them to their own throats, claiming that the vote that chose Alec as Consul was unjust. They demanded everyone who was not a member of the Cohort to leave Alicante, forever cut off from their homeland; that they would board themselves up in the city to save it from corruption, or die for the cause. Not willing to build a new Clave on the blood of so many young Shadowhunters, Alec agreed to the terms, causing the Clave to restart in exile and the Cohort to live in a self-made prison.