- "I pledged allegiance to the flag of the once United States of America. To the republic for which it claimed to stand. But we've become a nation under God forsaken fools. Highly divisible. Liberated by lies. Justified by complacency. Moral high ground it was built upon has already begun to erode. The blood of the fallen seeping in, widening the chasm, washing away the very land our men died for. No, a house divided against itself cannot stand. What good is a folded flag, or a heart-shaped medal to a grieving family? Our nation has become indifferent to sacrifice. Apathetic to the ideas of our forefathers. The time has come for Wolves to lay claim to this land. The betrayal we faced gave us liberty. Now we wage war against this plague with fear and retribution for all."
- — Walker
Fourth generation Army, West Point halfback, Walker graduated top of his class. Bucked a family-groomed strategic command career for field operations. Delta Force wanted him after he broke the record for "land navigation" test, and he was recruited by the Ghosts. Part of the need-to-know RET Team, assigned for borderline retaliation operations against dirty targets under US or American Ally protection. Currently deployed in more "standard" operations worldwide as a confirmed Ghost Team Leader.
The career path of young Cole D. Walker from North Carolina was straight as an arrow. His unshakable faith in his mission and his craving for results led him right to the heart of the battle, fighting for the sake of his country and his family. Nomad met Walker twice on deployment: first in Bolivia in 2019 and later in the Middle East, after which Nomad lost track of him. The fact that such a man could turn against fellow Ghosts is definitely bad news.
- "Y'all are Ghosts. Top tier operators. The quiet professionals. Bravest of the brave. Tip of the spear - all that and a bag of chips. But even a bad motherfucker needs help once in a while. Good thing for you, I'm a Ghost too."
- — Walker (In Operation Oracle)
During Operation Kingslayer, Nomad and his team would be called by Bowman to extract Skell Tech's R&D Technical Director Daniel Rodriguez Arellano who has been arrested by Unidad. The asset has knowledge of sensitive U.S. industrial secrets that must be protected.
They would also meet Major Cole D. Walker, a fellow Ghost Team Leader with his own agenda. He found out that Daniel was the one who designed an advanced surveillance drone for Unidad. Then Unidad weaponized it which killed Walker's teammates Sergeant Major (SGM) Jeffery K. Griffin and Master Sergeant (MSG) Alejandro J. Sanchez.
- "I'm a Ghost too. I would expect nothing less."
- — Walker (In Operation Greenstone)
At some point between 2019 and 2023, Cole was promoted to the rank of Lt. Colonel and became the secondary commander of the Ghosts. In February 22nd, 2022, he and Nomad along with several Ghosts were deployed in the Middle East running counter-terrorism operations.
Following several complications, Cole went rogue, alongside a number of Ghosts sympathizing with him, creating the Wolves and launching an attack on the Ghosts' headquarters at Fort Bragg. They executed a senior Ghost and killed several others. However, the remaining Ghosts under Nomad and Mitchell repelled the Wolves, but they were unable to catch Cole, who along with his Wolves escaped. He traveled to Auroa where he took great interest in Skell Tech's military technology and Jace Skell made him as Skell Tech's military adviser. He later rallied a PMC named Sentinel on his side and took control of Auroa.
Since then, Cole started using both of the company's resources and drones to track down the people who killed his teammates in Bolivia back in 2019. At the same time, he used a UCAV to kill a political candidate who was linked to the murder of his teammates. He proceeded to shut down all communications and took out a U.S. Navy cargo ship, the USS Seay, that was located off the coast of Auroa.
Cole ambushed the Ghosts, who were being led by Nomad using drone swarms. He and the Wolves might have killed all the Ghosts, including Weaver, except for Nomad, Vasily, Fixit, Fury, Holt and two others. Midas, however, is MIA. In the end, Nomad successfully killed Walker at Howard Airfield. With his dying breath, Walker respectfully returned his dog tags to Nomad.
- Walker is played by The Punisher star Jon Bernthal using voice and motion capture performance for Operation Oracle downloadable content and Ghost Recon Breakpoint.
- His plate carrier has the words "BORN TO HUNT" carved into it.
- His 2 dog tags say:
- COLE D
- A P0S
- His signature sidearm in Operation Oracle is the D50.
- His bracelet Lion's Den on his right arm can have the Executioner CQC Finisher and has his unique right arm Ghosts tattoo (Walker Tattoo).
- His RET team in full name is Retaliation Teams.
- In Tom Clancy's Ghost Recon Breakpoint he has a 3 signature weapons are a Designated Marksman Rifle Massoud 308 - 'Silver Stake Tactical' in Blackened and Bare Metal color, a Customized Fictional Revolver handgun - 'Sharp Thunder' in Polished Metal color and a Bush Knife having Fictional Design which has Black handle with Metal blade.
- His DMR 'Silver Stake Tactical' has an UBR GEN2 Collapsible Stock, an EXPS3 scope with 3x Magnifier, a Precision Bipod, a Suppressor Cover Silencer, the MBUS PRO Sights and an Angled Fore Grip.