Axl

Axl (アクセル) is a playable character from the Mega Man X series. He has an important role in two of the games he has appeared in so far, effectively making him the third playable protagonist of the X series alongside Mega Man X and Zero.

Personality
Axl is cocky and has a sense of humor. Although that black armored reploid can be whiny when there is nothing to do, which can get on X and Zero's nerves, Axl is kind-hearted and always cares about others. He often brags about how he is one of the best and this can get him into trouble.

Axl can also be noted to have a sort of fondness for battling, which puts him in contrast with X. However, this may turn out to be a good thing, as seen in Mega Man X8 when twice he convinces X to continue fighting against their enemies, at least until the war is over.

Mega Man X7
In Axl's debut, he was a member of the bounty hunter syndicate, Red Alert. However, after questioning their methods, he escapes their base, and was "captured" by Zero. When the conflict between his old group and the Maverick Hunters began, Axl felt himself responsible, since Red Alert was challenging the Hunters for his custody. In order to make up for his mistakes, he joins forces with Zero and the Hunters to stop Red Alert, although they were initially reluctant to let him join. It was through Axl and Zero's combined efforts during the conflict that X came out of retirement to fight again.

Together, the three infiltrate Red Alert's base of operations, the Crimson Palace, and confronted the leader, Red, himself. After defeating Red, the Hunters learn that Sigma is at it again, manipulating Red Alert from the shadows. Even after defeating Sigma, twice, he comes back, and punches Axl through a wall. Sigma also swore to have a new form when he does return. Red reappears, and just when Sigma is presumably attempting to possess him, Red uses Axl's pistol to blast Sigma out of the palace through a window. It turns out that "Red" is actually Axl copying his DNA to trick Sigma into defeat. X, Zero and Axl then escape the crumbling palace.

Mega Man X8
Axl joins X and Zero in the forest outskirts of the Jakob Orbital Elevator, investigating a crab-like Mechaniloid. This time around, Axl is now a full-time member of the Maverick Hunters and was trusted by both X and Zero.

After the first mission, the three encounter (Axl for the first time) Vile, who kidnaps the director of the Jakob project, Lumine. After this incident, a series of Maverick attacks begin, all revolving around the involvement of New Generation Reploids. It turns out that Axl is a prototype of these Reploids, since they have the same copy chip as he did. Some of the Reploid Mavericks think of Axl as a traitor, with him siding with "Old" Reploids. The "mastermind" of the incident is revealed to be Sigma again, and the three Hunters chase him to the his palace on the Moon (and Sigma reveals that, even if Axl didn't side with the "old" Reploids, he still wouldn't have allowed Axl in anyways, as Axl was nothing more than a "prototype".). However, after Sigma is defeated (presumably for the last time), Lumine reappears, saying that Sigma is no longer of any use (Thus implying that Sigma was actually a puppet, and that it was actually Lumine who was the Mastermind). Axl and his friends defeat Lumine, but the latter has one last trick up his sleeve: something lashes out of the lifeless shell of the villain and hits Axl, before finally being destroyed by X and Zero.

When the group begins their descent back to Earth, comatose Axl is carried in X's arms. In his cracked forehead crystal shines a fragment of what Lumine hit him with.

Mega Man X: Command Mission
Seemingly recovered from his comatose state after the events of X8, Axl comes to Giga City a short time after X and Zero did, believing that his copy abilities may have originated there. He joins X's party midway through a mission to infiltrate Mach Jentra's Ulfat Factory. Also, he tells X that someone was using his copy ability to mimic Wild Jango to infiltrate Giga City shortly after they defeated Jango the second time (the culprit later revealed to be Colonel Redips himself.). Presumably, his copying abilities grew stronger, as he is now able to copy many of the bosses DNA and transform into them, whereas it was mentioned in X7 that he can't copy bosses, just their abilities. It is speculated by fans that Axl's improved copying abilities may be connected to Lumine's final attack on him in the rather ambiguous ending of X8.

Arsenal
Axl has a special ability called Copy Shot, which allows him to disguise himself as certain non-boss enemies; in the games that it's featured (particularly in Mega Man X8), these transformations can be used to solve puzzles. In Mega Man X: Command Mission, Axl's Action Trigger, a special command introduced in the game, allows him to turn into defeated bosses such as Wild Jango, Silver Horn, Mad Nautilus, Mach Jentra, Incentas, Depth Dragoon, Rafflesian and Ninetails. This allows him to take a role akin to a summoner in more traditional RPGs.

Following the trend started by his partners X and Zero, Axl can upgrade his armor to improve his abilities. In Command Mission, his Hyper Mode allows him to turn invisible and virtually invulnerable while it lasts. Like most Hyper Modes, however, this is only temporary.

Trivia

 * It is speculated if Axl himself is part of the main timeline, as no mention of him is ever made in the Mega Man Zero and ZX series. If he is, then the question is on whatever happened after the X series.
 * Interestingly, even though Model A was an unofficial homage for Axl, how he copies and mimics enemies DNA cores is slightly different: Axl uses Copy Shot to transform into them, while Model A just copies their DNA core data by defeating them. Also, it seems as though Model A's ability is limited to powerful enemies (eg, Pseudoroids and Mega Men), while Axl can copy various enemies, and even bosses to a certain extent.
 * Axl is the name of the band leader of Guns N' Roses, and it is doubtful that it's a coincidence with Mega Man X5, which the Mavericks had names related to Guns N' Roses; and Mega Man X3, with Neon Tiger's stage music sounding very similar to the song "My Michelle."
 * Axl makes a cameo in Zero's ending of Tatsunoko vs. Capcom: Ultimate All-Stars, where he, Alia, and X discover Zero injured on Earth's moon. This also marks the first time he appeared in a game since Mega Man X: Command Mission.