The Phenomena Weapon Dispossession Operation (事象兵器奪取作戦 Jishō Heiki Dasshu Sakusen) was a major event that happened in 2193 AD in the 4th Hierarchical City of Naobi. It heavily involved both Sector Seven and the Novus Orbis Librarium. Now, only two survivors of the event remain; Iron Tager and Azrael.
Due to an anonymous tip, Sector Seven discovered the presence of the Nox Nyctores - Deus Machina: Nirvana buried deep within the Hierarchical City of Naobi, fearing that the NOL had also received the same news, Sector Seven hired a mercenary squad to be sent to the ground level and excavate the Nox. However, when the squad had excavated Nirvana, they encountered NOL soldiers and the two groups engaged in combat. Many lives were lost as Nirvana reactivated due to a small amount of energy left within it, and it attacked, killing several troops. To add to the hopelessness of the operation, Azrael appeared and wiped out every single combatant, with the exception of Tager, the commander of the squad, who had suffered a mortal wound from both Azrael and Nirvana. When Sector Seven realized that the odds were stacked against them, they had Tager and Nirvana evacuated as soon as possible. It was from here that Tager's memories were wiped out after the life-saving surgery Kokonoe performed on him.
The aftermath of the event was somewhat devastating. Bullet, who belonged to the squad, has been searching answers for what happened during the event for the last 5 years since it happened. It is because of this that she is on the constant hunt for both Kokonoe and Relius Clover; two major players in the beginning of the event and its immediate consequences.
The majority of the details concerning the event are sketchy, due to multiple sources conflicting, such as the short story That which is inherited and comments dropped by Azrael in BlazBlue: Chronophantasma.