Prior to joining the Maverick Hunters, Axl was part of an organization of Reploids with questionable methods. His conscience eventually plagued him enough that he left that group to join the Hunters, and he soon became involved in the fight against Sigma and his Mavericks. (MMX)
Axl later joined X and Zero in an attack on Sigma's latest fortress, and remained behind to engage the resurrected Vile while X went ahead to confront the Maverick leader. Axl relished the opportunity to face Vile, and took a shot at Zero for giving him such a hard team when he joined the Hunters considering that Vile had once been a member. Zero then ordered him to take a flanking position and prepare to utilize weapon data that he had copied from an enemy Maverick. Following Vile's defeat, Axl and his two teammates set out to chase down Sigma, who had escaped to Mobius, by using Sigma's own machine and advice from Silver the Hedgehog to open a Genesis Portal. However, they ended up in the Sonic Boom Zone by mistake, and were forced to rely upon help from Sticks the Badger and her unlikely teammates Comedy Chimp and Fastidious Beaver. After "persuading" the Orbot and Cubot of that world to help them, they entered another Genesis Portal to resume their search. (SU: #76; WUB: MM; SB: #8)
The unlikely party of heroes eventually made their way to Mobius Prime at the same time it was being merged with a past version of the Maverick Hunters' home world. Having discovered that Sigma was behind the creation of the Unified World with his Unity Engines, they joined forces with the Knothole Freedom Fighters and Robot Masters under Mega Man and boarded the Sky Patrol in order to hunt the villain down. They eventually learned of his location on the Lost Hex from Dr. Ivo "Eggman" Robotnik and Dr. Albert W. Wily, who arrived aboard ship courtesy of Xander Payne. Upon arriving in Lost Hex airspace, they were attacked by Sigma's brainwashed minions, the Deadly Six, and an army of Mechaniloids. While they scored early victories against the villains, the Deadly Six turned the tables by using their technology-controlling powers to force Axl and his robotic teammates to attack their organic allies. Unable to control his actions, Axl became terrified that he was becoming a Maverick, and Zero tried to calm him down and encourage him to fight the manipulation as best he could. Luckily, the evil doctors freed the robots and defeated the Zeti with their Egg-Wily Uppity Robot Scrambler Cannon. However, Sigma then emerged in a massive new body from the Lost Hex, accompanied by an army of Time-Cloned Mavericks. (MM: #50; SU: #77; SB: #9; StH: #273)
Axl was greatly distressed to recognize several of his former comrades and other fallen Mavericks in the ranks of the army, but X assured him that they were only duplicates and had to be destroyed. Sadly, their previous battles left the heroes barely able to hold their own, and Sigma soon called back all but a handful of Mavericks. While four of them prepared to finish off Axl and his allies, the rest were dispatched through Genesis Portals to invade various worlds and plant more Unity Engines so that Sigma could absorb their power. Fortunately, help arrived in the form of several heroes from the Street Fighter Zone, whom Sticks had recruited following an unexpected trip there. After the four Mavericks were defeated, Sally Acorn organized the heroes into smaller groups in order to head out in pursuit of the Mavericks and to recruit other otherworldly allies to their cause. (MM: #51)
A rookie Maverick Hunter, Axl is eager to prove his mettle against tough opponents, and not afraid to tease his superiors. However, due to his inexperience he is also somewhat less prepared to deal with shocking or disturbing experiences.
Like X and Zero, Axl is capable of copying weapon data from enemies and using their arsenals in battle, to the point of being able to take on the physical appearance of some foes. He also employs a pair of pistols as his signature weapons.