As Outcast attacks escalated, Walker and Stone utilized the attacks as a pretext to initiate martial law. As Walker and Stone began realizing the potential drone technology that Skell Tech had developed, Stone and Walker quietly began massing Sentinel and Wolves forces into the island's abandoned military sites. By 2025, Sentinel was contracted by Skell Technology to provide security for its operation in Auroa shortly after the devastating attack by the Outcasts that led to the deaths of 30 employees and the complete destruction of a building. Encountering Trey Stone, the Wolves decided to align themselves with the Sentinel Corporation, serving as its elite special forces unit. However, owing to its independent nature, the Wolves lacked the means to continue funding his campaign against the United States government. Rallying several Ghosts, both former and current who sympathized with him, Walker and his men went rogue, establishing the Wolves. In response, Walker returned to his base and executed his commander. Leaving the armed forces, Walker suffered a mental breakdown, believing that he had suffered an injustice, with his suspicions over the apparent politicization of the military now fully cemented. Subsequently, Walker was court-martialed and medically discharged from the armed forces. After attempting to kill Walker and plant evidence, an angered Walker executed him. His frustration eventually came to a head when Vaughan accidentally killed an Afghan villager following a scuffle.

Throughout the tour, Walker grew irritated as Vaughan's incompetence that often hampered the unit's efforts to combat insurgents. Sometime in 2022, Walker was deployed to Afghanistan alongside fellow Ghosts Nomad and Josiah Hill, operating under the command of Vaughan.

Expressing his frustration with several of his colleagues, many agreed with his view as discontent quietly brewed. Angered at the apparent indifferent attitude by the military hierarchy over the deaths of his team in Bolivia, Walker grew increasingly frustrated at what he perceived was the increased politicization of the military.

Silverback wolf