Northern War

The Northern Campaign was a huge battle that took place in the North in the town of Pieta amongst 24 Claymore warriors and several Awakened Beings under the orders of the Abyssal one Isley.

Phantom Miria, ranked #6, was the overall leader of all the claymores attending, being the highest ranked. She split the group into 5 teams, to function just as hunting parties act as a way of helping to gain experience for all warriors involved.

As stated by Miria, this mission was intended to be just a road-block to the Awakened Beings who were marching South and also a suicidal mission (with nearly zero percent chance of success) in order to kill off all the warriors whose behaviour was suspected to be a potential threat to the Organization's true purposes. To avoid the death of every warrior involved, Miria worked on a plan that would also prevent the Organization from sending the survivors on another suicidal campaign by faking their own death.

Before the final battle, Miria had all the claymores take half of a suppressant pill. This way, their abilities would not be affected. However, if they were knocked unconscious, the pill would get fully effective, hiding their yoki so they would seem 'dead'. Because of this strategy, seven warriors were able to survive: Miria herself (#6), Cynthia (#14), Deneve (#15), Helen (#22), Tabitha (#31), Yuma (#40) and Clare (#47).But it is unknown how the other fellow warriors was killed since they didn't show their death scenes.Ontop of that it's possible that they had ditch the mission.

Assignment
After their battle against Riful, Clare and Jean were spotted by Rubel and Rafaela. Riful told that a desertor like them would be most likely executed on the spot, but that the Organization has decided to give her another chance should they perform a special task. They were told that the mission would be, as part of a large group of Claymores, to exterminate several Awakened Beings who had fought and killed warriors Eva, Kate and Lucia on the Northern Lands. Rubel also told Clare that Raki was captured by slave traders and taken to the North, who convinced her once and for all to take part on the mission.

First Battle
As Clare and Jean arrived at the town of Pieta, they met Helen, Deneve and Miria, who were also assigned to this mission. As the highest ranked warrior and overall leader of the assignment, Miria divided the 27 warriors assigned into four teams of five warriors and one of four, each being commanded by one team leader: Miria herself, Flora (#8), Jean (#9), Undine (#11) and Veronica (#13). At the end of the day, Miria explained to Clare, Helen, Deneve and Jean what she had found out about the true purpose of the operation: to merely slow down the Awakened Beings that were heading South and to get rid of the less obedient warriors, whose behaviour may come to be a potential threat to the Organization's intends. The meeting was interrupted by three Awakened Beings, that suddenly stormed into the town, attacking everyone. However, the group managed to successfully kill them without a single loss. Later that night, Miria introduced her plan to the entire group: had all the claymores to take only half of a suppressant pill before the battle next day. This way, their abilities would not be affected. However, if they were knocked unconscious, the pill would get fully effective, hiding their yoki so they would seem 'dead'.

Second Battle
After the three Awakened Beings sent by Isley had not returned, he ordered Rigardo to entirely destroy Pieta, along with any living creature inside. As Rigardo arrived at the battle, he started by killing all the team leaders except for Jean (who survived the attack but was severely injured) and Miria, who managed to hold on by using her Phantom Move ability. As Miria's yoki started to grow weak, Clare interfered in the battle, only awakening her legs so she could match Rigardo's extreme speed. As the battle went on, Clare managed to kill Rigardo by also awakening her arms, thus she crossing her limit as her body started to fully awaken. Heavily wounded, Jean managed to pull her back, sacrificing herself as Clare's body was out of control. However, even though Rigardo was defeated, only a few claymores managed to survive to fight the remaining awakened beings, and were all defeated in the end. Only seven of them survived, thanks to Miria's plan: Clare, Helen, Deneve, Cynthia, Tabitha, Yuma and Miria.

After the Campaign
The survivors of the Northern Campaign deserted and hide in the northern wastes for seven years, hiding their yoki so the Organization would presume them dead. As a consequency of the northern war, the Organization also changed their policy, hunting awakened beings actively instead of only when they were assigned to.