The Weapon begged the Master Chief for help, but, worrying that the AI had been compromised, he went through the authentication to manually delete the Weapon instead. Later, while interfacing with Halo in the Nexus, the Weapon was trapped in the system by the Harbinger. The Weapon reveals that she stole Pyre's encephalon from the Harbinger. When nothing happened to her, the Weapon suggested that she was just being paranoid and the Master Chief dodged her question about what he was saying while activating her deletion protocol. With no other choice, the Master Chief allowed the Weapon to proceed, but he discreetly activated a deletion protocol for the AI just in case. The Master Chief suggested stopping and creating a stalemate, but the Weapon warned him that the Harbinger is close and that she would eventually find a way. The Weapon realized that it was a trap with the Harbinger trying to break the deadlock on starting the Spires by combining the Weapon's routines with the Monitor's. Throughout her hacking, the Weapon was observed by another presence and it was only on the fourth beacon that she realized that it was actually the Harbinger.

However, in order to help the Master Chief access the Command Spire, the Weapon was forced to interface with four Forerunner beacons in order to override a lockdown on the Command Spire. Recovering the framework that the Weapon had used to lock down Cortana, the two witnessed echoes of Cortana's life scattered across Zeta Halo's systems. Not knowing how or why her deletion was averted, she was recovered and accompanied him across Zeta Halo, which was now controlled by the Banished following the crippling of the Infinity. Six months after the defeat of Cortana, the Master Chief was revived and returned for the Weapon, whom he was surprised to see was still functioning. As a result, the Weapon was left active within the ring's foundation, believing that the Master Chief was due to come back for her. She also deactivated the Weapon's deletion routine so that she could accompany John-117 during the struggles that lay ahead. In reality, Cortana had willingly destroyed herself and damaged the ring in order to prevent Atriox from using it against humanity. Cortana was destroyed, though not through means apparent to the Weapon. Once on the Halo, the Weapon was able to lock down Cortana in the Silent Auditorium. Meanwhile, the Master Chief stayed behind on the Infinity to hold off the Banished as Lasky was escorted to a dropship. As the ship quickly became overrun, Captain Thomas Lasky ordered for the Weapon to be deployed immediately. Shortly after the Infinity arrived at Installation 07, she was ambushed by a Banished boarding party force led personally by Atriox. Defeating Cortana Main article: Battle for Zeta Halo

Upon the Weapon's successful deployment, her deletion routine would be executed. Halsey introduced the Weapon to the Master Chief, and he was briefed on the plan to capture Cortana and deliver her to the UNSC Infinity for termination. Halsey created the Weapon to be an exact copy of Cortana with any information that could compromise the Weapon removed by Halsey. The contents of the bins, the remaining cloned brains from Halsey's creation of Cortana, were used by her to create the Weapon for the mission of entering an installation to imitate Cortana and lock her down for retrieval. Halsey insisted that what they were retrieving was the key to stopping Cortana, although she warned John-117 that while it would not be easy, it was the only option that they had. Catherine Halsey dispatched Blue Team on Operation: WOLFE to retrieve three cryobins and a lockbox from a cryovault beneath the ruins of CASTLE Base.

Halo infinite weapons