Dr. Wily built the Wily Walker as a walking weapons platform with anti-personnel and anti-armor support and decay-resistant chemical weapons to gain sponsorship from the military. Although Wily claimed that he only wanted to show its versatility and that he would have removed the chemical weapons for its final checks, the use of those weapons got him sanctioned for unethical robotic experiments. Surprisingly, the Walker was neither seized nor destroyed by the military, and its chemical weapons were also never removed, though Wily's comments about its location being too dangerous to dismantle suggest it was left there to avoid worker fatalities than anything else.
Years later, Dr. Wily deliberately leaked its location in a hidden lab in a mesa to his fellow scientists Dr. Light and Dr. Cossack to lure their Robot Masters (Mega Man, Bright Man, and Pharaoh Man) into a trap as well as buy enough time for the third generation of Robot Masters to finish up his castle. While sending them the "deactivation" code, it actually activated the machine, apparently resulting in Mega Man's death when sacrificing himself for Bright Man. However, Mega Man survived (with Mega Man also discarding his helmet in the process) and, after freezing it in place thanks to modifying Bright Man with a new ability, proceeded to level the room the Wily Walker was in to bury it. Unable to safely destroy it, Dr. Light has it neutralized with a special circuit board and left with an information module, in the event future generations happened to uncover it.
In the future, X and Dr. Cain rediscovered it inside the lab, having been deactivated a century earlier. They eventually removed the power core in the hopes of salvaging any information on the Wily Walker (which they believed to be a giant Mechaniloid), although it ultimately awakens. It then tries to escape the mesa, although one of the Reploid archaeological staff, Samantha, pulled the alarm to ensure that both the dig members and the tourists evacuate the premises. X then proceeded to fight it off while Dr. Cain, remorseful that he had ignored X's warnings about it potentially being a weapons platform, tried to find a way to shut down the weapon via the relics, as well as called in the Maverick Hunters at X's request. The Maverick Hunters, composed of Zero, Vile, and three more unnamed Reploids proceeded to fight it off while X, at Zero's suggestion, tried to track down Dr. Cain to see if he is in need of assistance. Xander Payne also witnessed the Mechaniloid, and mistakenly believed that he came to the time that the revolt started (being unaware that he had actually time-travelled a hundred years after his present). Dr. Cain eventually stumbled upon the left-behind capsule detailing some things about the Wily Walker, including that it was equipped with chemical weapons. X then warned Zero and Vile of this development, with Vile proceeding to fire at a highway to prevent the Wily Walker from escaping, resulting in the casualty of one human and several injured. When Sigma arrived, the Wily Walker instantly recognized him as a threat, and proceeded to ready deployment of its chemical weapons. However, Sigma and the Hunters were able to stop it before calling for Flame Mammoth and his team to head over to dismantle it, as well as calling in Toxic Seahorse to disarm the chemical weapons, ending the threat of the Wily Walker.
- The Wily Walker bears a heavy resemblance to the Wily Machine 3, which was noted by Mega Man himself in issue 47.
- Both the activation code Wily gave to Mega Man and the code for activating the door are codes from the game Mega Man 7.
- Originally, the Wily Walker had white eyes with black pupils just like other robots from classic Mega Man timeline. However, after Mega Man shot its face with a charged shot, the eyes got destroyed, exposing the internal black eyes with red glowing pupils and gave it more menacing look.
- According to its HUD display, its weapons systems included seven rear guns, a front gun, a bottom gun, as well as SR and LR chemical weapons. Of these weapons systems, only the bottom gun, the first, third, sixth, and seventh rear guns, and the LR chemical weapons were online by the time it regained functions in X's time period.
- During the conflict with the Maverick Hunters, the walker identifies Zero as having an Wily-unique signal, hinting at Zero's creator.
- One of the reasons why the Wily Walker was disapproved can be found in the 4th Hague Convention from 1899-1907, which is still in force in times of warfare.
- SECTION I
- CHAPTER I - Means of injuring the enemy, sieges, and bombardments
- Art. 23. In addition to the prohibitions provided by special Conventions, it is especially forbidden
- (a) To employ poison or poisoned weapons...
- The Wily Walker was given an indirect mention in the sub-story The Choice in Mega Man Issue 50 (Archie Comics), where Mega Man, upon giving a pep talk to X convincing him not to tell Light to not create him, mentions the possibility of one of Wily's inventions running amok.
- Elements of the Maverick Hunters' confrontation with the Wily Walker resembles their fighting against a Maverick Mechaniloid in the beginning of the anime prequel OVA to Mega Man: Maverick Hunter X: The Day of Sigma.