Mega Man X9 (known as Rockman X9: The Elf War Crusade in Japan, Mega Man X9: The Lost Chapter in Europe/Australia) is a sequel installment to the previous Mega Man X: Command Mission. It is available for the PlayStation 3, Wii U, Nintendo 3DS and Xbox 360 systems.
Mega Man X9 takes place between Mega Man X: Command Mission and Mega Man Zero, yet more likely follows the Mega Man X8 plot on its own, of which it does. In the year 22XX a long time ago, X (along with Zero and Axl) had been constantly protecting humanity and the Reploids, themselves. Regardless, Sigma is now dead and Lumine has been revived from defeat... by a dark entity that knows what the situation became of him! During this time, Axl started going through symptoms of rage and insanity, to a point where Zero told X that the latter was becoming "one of them" (a Maverick). Now set in the year 25XX, Signas has recently discovered a more powerful Maverick, one that claims to have a higher ranking above all: Incubus. He sended this data immediately over to Alia, Layer, and Pallette, whom are in the process of discovering Axl's condition. Both X and Zero (now revived from Zero 4, in his original incarnation) heard this as an important crisis and decided to embark on the mission of killing this unstoppable Maverick, along with a slightly disturbed Lumine and an enslaved army of new generation Reploids. The subtitle is "Soulless Carnage".
- X (Rockman X in Japanese): Enraged over Axl's virus that he believed that the latter has recovered from, X wants revenge and now is on a rampage in order to seek out every Maverick he finds, and will destroy it just to protect the peace and harmony one more time... Mega Man X's X-Buster weapon is now equipped with a built-in saber with a purple tint. Voiced in Japanese by Takahiro Sakurai and English by Vic Mignogna, since Mark Gatha became a doctor.
- Zero: He wants more answers concerning why Lumine has been revived in a darker state. So to put it this way, he tags along with X to find a way to restore Axl's in the condition he is in. Like X, Zero now sports a change: the ability to dual-wield or separate his Z-Saber. He is voiced by Ryotaro Okiayu in Japanese and Johnny Yong Bosch (who voiced the latter in Marvel vs. Capcom 3) in English.
- Axl: Lumine has threatened him once more, and now Axl is acting insane and violent after his recovery from X8. He is only playable if you beat the first five Mavericks or play the whole story on Hard. One distinct change in Axl overall is the addition of stealth and hand-to-hand combat maneuvers... The latter is now voiced in Japanese by Kenichi Suzumura (since many people believed that a woman voicing Axl was a little ridiculous), and in English by Yuri Lowenthal.
- Alia: She is currently finding out Axl's condition, alongside Layer and Pallette, even as we speak... Voiced in Japanese by Rumi Kasahara and Laura Bailey in English.
- Iris: After Zero thought she was dead, she was remade again by Zero. She has Zero's single wield sword and she has the same voice from Mega Man X4 and playable if you beat 5 mavericks as Zero.
- Layer: Her feelings for Zero may have developed overtime after X8... Like Alia and Pallette, Layer is trying to examine Axl's tragic problem. She is voiced by Sonoko Kawata in Japanese and Wendee Lee in English.
- Pallette: Currently looks over Axl alongside Alia and Layer. As it may look personality-wise, Pallette has matured after the events of Mega Man X8. Voiced by Haruna Miura in Japanese, and Colleen O'Shaughnessey in English.
- Signas: Signas has recently found more data resolving around Incubus, the new Maverick and his army of enslaved Reploids. Unlike past games, he serves a more major role in the game, even as far as being able to play as him (only by beating Hard Mode twice). Now voiced by Fumihiko Tachiki in Japanese and Troy Baker in English.
- Lumine: He has been revived by Incubus shortly after being defeated by X, Zero, and Axl... Lumine now has darkish-red eyes and a more unstable presence: wherever Incubus is sighted, Lumine is not too far behind! Voiced by Junko Noda in Japanese and Mona Marshall in English.
- Incubus: The main antagonist of Mega Man X9. All of what's known of him is that the latter is a shadowy figure that outranks Sigma in height, and has massive wisdom, with a downfall: his outlooks on peace and harmony! To become stronger, whenever a Maverick or a Reploid is destroyed, Incubus's power increases within every reach... Voiced by Naoya Uchida in Japanese and Paul St. Peter in English.
- Vile (VAVA in Japanese): He now seeks massive power and strength in order to defeat the Maverick Hunters all at once... if he ever dies, then Vile will drag the Maverick Hunters down to Hell with him, whenever they like it or not! Vile's color scheme is purple, just like in his original game appearances. Voiced by Mugihito in Japanese and Kirk Thornton in English.
- Dr. Light: He is the one responsible for the creation of both the classic Mega Man and X, himself. Like in past games, Dr. Light is depicted in few sections of one level to be giving the player information or new abilities. Voiced by Tomohisa Aso in Japanese and Doug Stone in English.
- Bass (Forte in Japanese): He is the first sub-boss of Mega Man X9. Unlike the classic version, who is driven with madness and power, in the Mega Man X universe, Bass is disgustingly a polite individual (like in the Battle Network manga) who seeks power not to become stronger, but to reign supreme. Treble does not appear with Bass in this installment, and for the most time, the latter wears a tan cloak over his attire. Voiced in Japanese by Keiko Nemoto and Liam O'Brien in English.
- Stage One: Neo Matter (CV: Masakazu Morita - JPN; Reuben Langdon - ENG)
- Stage Two: Red Masquerade (CV: Haruka Tomatsu - JPN; Stephanie Sheh - ENG)
- Stage Three: Frost Dragon (CV: Matsuri Mizuguchi - JPN; Spike Spencer - ENG)
- Stage Four: Inferno Fox (CV: Nobuyuki Hiyama - JPN; Steven Blum - ENG)
- Stage Five: Blitz Thunder (CV: Showtaro Morikubo - JPN; Crispin Freeman - ENG)
- Stage Six: Chrome Oblivion (CV: Mika Ito - JPN; Barbara Goodson - ENG)
- Stage Seven: Raging Destroyer (CV: Tomomichi Nishimura - JPN; Jamieson Price - ENG)
- Stage Eight: Soul Reaper (CV: George Nakata - JPN; Daemon Clarke - ENG)
The style of this game is reminiscent of Mega Man X8, only this time: a new multiplayer option has been enabled, and the order of Mavericks have been automatically selected for the player; therefore, he/she has to go in the order of what has been developed in the gameplay, overall. However, like many previous titles, you can still copy the defeated Maverick's signature ability after you have cleared the stage. Graphics have changed slightly to a more crispy, HD style reminiscent of Bleach: Soul Resurreccion (a hack-an-slash action game for the PlayStation 3 available August 2011), and the music has been beefed up to fit the style of Mega Man X9's overall mood. Between the game and before you fight the Maverick, there are anime-styled cutscenes (like in Mega Man 8 and X4) one will encounter, with each of them being animated by Japanese studio Bee Train, with all character designing by Satoshi Ohsawa.
The same graphics from Mega Man X8 are in use for this title and like almost every Mega Man game, there are eight Mavericks in all to beat in different locations before fighting a sub-boss, and then the final boss. This marks the first Mega Man to do two new things: first installment to appear on a next-gen console and first installment to have a language switch option (unlike Mega Man X7 and X8, which only had this on the PC ports). Clearly speaking, this is also the second game where Inafune did not use any direction; that position went to Hideaki Itsuno.
There is an OVA trailer called Mega Man Zero 4: The After follows the events after Mega Man Zero 4 when Zero sacrificed himself. It takes place between Mega Man Zero 4 and Mega Man ZX.