Ultimate Armor

The Ultimate Armor (アルティメットアーマー) is a secret armor for Mega Man X that bestows the most all-around fighting power in any of the games in which it appears. Because it appears in so many games in the series, it has the most recurring traits of any of X's armors.

Mega Man X4-X6
In Mega Man X4, X5, and X6, the Ultimate Armor grants all of the abilities of the Fourth Armor, and appears as a modified design of that same armor. Its buster's charged shot is the Plasma Shot of the Fourth Armor, and its powerful Nova Strike can be performed an unlimited number of times.

In Mega Man X4, even if a code has been inputted, the armor must still be obtained through one of Dr. Light's hidden armor capsules (the easiest of which is in Web Spider's stage). Until then, X's secondary turquoise hue is changed to a lighter purple one, a tell-tale sign that the code has been entered correctly. In X5 and X6, the armor will be equipped when starting a new game, as long as the code has been entered correctly.
 * In X5, once the code is entered correctly, the Ultimate Armor will replace the Fourth Armor & the Fourth Armor will be unavailable for the rest of the game.
 * In X6, unlike in X5, X not only owns the Ultimate Armor but also retains the Falcon Armor once the code is entered correctly.

Special Weapon usage while equipped with the Ultimate Armor varies from game to game: In X4, this Armor grants unlimited usage of Special Weapons in their normal shot forms. Weapon Energy will still be used when Charged Shots are used.

However, in X5 and X6, this Armor will work like the other Armors used in their respective games with the maximum shot capacity of the Special Weapons that X can use are automatically increased by 50%.

In Mega Man X5, there is a way to receive the Ultimate Armor without using a code. In the third station of Zero Space, there is a vertical shaft that leads to a special armor capsule. In order for this capsule to appear, X must not have any armor equipped. Entering this capsule as normal X will grant him the Ultimate Armor. However, he will only receive an armor program as opposed to equipping the armor right away (the same principle used when gaining the Falcon Armor and the Gaea Armor except that only one program for the Ultimate Armor will be given for all parts and not 4 individual programs). This will make X own a total of 4 armors in the game, including Fourth Armor (as long as Fourth Armor X is chosen as starting character).

Mega Man X8
The Ultimate Armor may be unlocked through either a code, or by starting a new game from a save file that has been cleared while X is at 100% and all 8 Icarus and Hermes Armor parts are unlocked. Take note that the code option is available for the console version (PS2) of this game (as well as the later Mega Man X Legacy Collection 2 re-release) only and has no effect in its PC Version.

In this game, the Ultimate Armor appears to be a black version of the Neutral Armor, with its own violet glow. It is a separate option within the Neutral Armor selection, and thus cannot mix its parts with those of the Hermes and Icarus Armor. The most probable reason that a purple glow is used is that this Ultimate Armor fuses abilities of the game's two Armor Sets, Icarus (red) and Hermes (blue) into one single Armor.

This Armor has one uncanny ability that other Ultimate Armors do not have - it grants X unlimited usage of all Special Weapons obtained by Maverick Bosses, including charged shots. This is different from what the X4 version does in using weapon energy for charged shots only.

This version of the Ultimate Armor has a more powerful Nova Strike, at the cost of limiting its use since it now has its own weapon gauge. It will drain the entire energy gauge, but also has the quickest recharging rate, refilling the gauge in mere seconds. This version of the Nova Strike is more powerful when X's weapon gauge is augmented via Pallette's chip development. When used on a boss in Normal Mode or higher, most Bosses can go down in two hits; one Nova Strike will shave off most of the Boss' energy, leaving only a fraction so that that boss can use its Overdrive attack. Also, if used on Sigma before he automatically grabs the character, it will only reduce his health enough to initiate that segment of the fight. The way X performs his Nova Strike in this armor resembles that of the Blade Armor's Mach Dash in X6, covered in powerful destructive energy. Unlike the Mach Dash, however, it can only dash left or right.

Mega Man X: Command Mission
Here the Ultimate Armor is X's second Hyper Mode, and is earned by defeating the boss Rafflesian.

A stark change in appearance from previous armors in terms of design, but the color-scheme is back to white and blue, with red and yellow detailing. A disc-like object protrudes from his shoulders horizontally behind him. A large, green gem forms his chest, and a targeting display covers his left eye. Gatling batteries are on the front of his shoulders, and his arms change into a pair of large, pistol-like appendages from the elbow down. The legs and the top of the disc are also translucent. X's standard attack becomes a devastating beam attack called the Giga Crash fired from his chest, and his sub weapons are Impact Cannon and Strike Bullet. When equipped, X perpetually hovers in the air (presumably for the armor being too heavy to stand).

X's Action Trigger in this Hyper Mode is still called the Nova Strike, but functions much the same as the Final Strike. The higher X's WE is when the move is started, the longer X has to attack enemies.

Mega Man X Legacy Collection and Mega Man X Legacy Collection 2
X uses an unnamed armor based on the Ultimate Armor in the X Challenge mode. Except for the colors, its appearance is identical to the Ultimate Armor. It lacks the Nova Strike and has the Plasma Shot of the Fourth Armor in Mega Man X5, leaving one plasma ball behind. Like in X6, X can also use Zero's Z-Saber with this armor. He can also use the Special Weapons from past bosses. When used in a buster-only challenge, the majority of this armor is removed with the exception of the Foot Part.

Additionally, once X Challenge has been completed on Hard difficulty, the player will unlock a secret bonus stage in which the bosses are another X that dons the Ultimate Armor (X6 color) and Zero's "awakened" form from X5.

Project X Zone and Project X Zone 2
X dons the Ultimate Armor during the end of his finishing move, in which he hits the opponent with the Nova Strike and slams them into the ground.

Marvel vs. Capcom: Infinite
X will equip his Ultimate Armor during his level 3 hyper combo "Ultimate Strike," in which if the aura that comes from X putting on his armor connects, he hits his opponent with Nova Strike and ends by shooting them with a beam from his X buster.

He also assumes the Ultimate Armor in-story in an attempt to control the sheer power output of the Infinity Buster to destroy Ultron Omega, ultimately succeeding with the help of Doctor Strange and Morrigan channeling the various heroes power into him with themselves as magical conduits.

Puzzle Fighter
When X uses his super skill, "Ultimate Nova Strike", he dons the Ultimate Armor and attacks with the Nova Strike.

X4-X6

 * Foot Parts- Grants the ability to air dash or hover in midair. Midair hovering time is decreased if X moves.
 * Body Parts- Reduces damage taken by X by 50%. Allows X to use a wider range Nova Strike that does not consume any weapon energy. It also covers more distance than its X4 counterpart. Note, however, that it does require X to touch solid ground/cling to a wall before it can be used again.
 * Arm Parts- Grants the powerful Plasma Shot.
 * Head Parts- In X4, uncharged weapon usage was reduced to zero. In X5 and X6, this increases the maximum Special Weapon shot capacity by 50%, just like the Fourth, Falcon, and Blade Armor Helmets in their respective games.

X8

 * Foot Parts U - Movement speed and jumping height increased. X can also dash through enemies without damage, which is the combined abilities of Foot Parts H and I.
 * Body Parts U - Take half damage and will not be subjected to recoil from collisions with enemies/hazards. All HP damage will be converted to red bars which can be recovered while in reserve which is the same ability as Body Parts I. Also enables X to perform the Nova Strike that can annihilate enemies in one attack.
 * Arm Parts U - The X-Buster's fully-charged shot will be the Plasma Shot where it can cause multiple damage to an enemy. Weapon Energy usage for all Special Weapons (including their Charged Shots) will be reduced to zero.
 * Head Parts U - Enables use of the Shouryuken uppercut technique to attack enemies directly upward, similar to the Head Parts I but with a smaller attack width.

Secret Codes
Refer to the table below for codes used to gain use of the Ultimate Armor. The codes are listed with the button pressed and the number of times pressed next to it. In X4 and X5, highlight X on the Character Select screen and enter the codes. In addition, in X4, the shoulder buttons must be held until the actual game begins (after the cutscenes). In X6 and X8, highlight Game Start, complete the sequence of buttons, and press Start. While there is no way of knowing if the code is completed in X4 until the opening stage is accessed, in X5 and X6 a sound clip is heard if entered correctly, while a voice clip of X is used for X8.

Trivia

 * In X4, Dr. Light's Hologram mentions that the Ultimate Armor is incomplete and possesses potential risk to use. No problems are ever encountered during gameplay, however.
 * Ultimate Armor is possibly the most powerful armor, due to his destructive and reusable Nova Strike.
 * The armor in X5 is a slightly different color than in X4. The legs are a lighter blue, more similar to his usual color, and the purple parts of his upper legs, arms, and waist is his usual cyan color instead. However, if Zero is selected during the third Zero Virus stage in X5, X will be equipped with the Ultimate Armor with the X4 palette (and X4 special weapons Frost Tower, Double Cyclone and Soul Body), during their battle.
 * In X6, the Ultimate Armor has a darker color scheme. However, if the Buster is charged, the Ultimate Armor will resemble its original palette. The color scheme also found its way into the Ultimate Armor used in X8, albeit with the Neutral Armor as its design basis, instead.
 * The Ultimate Armor's Nova Strike is one of two Giga Attacks that is immediately available at the start of the game (in this case, X5 after entering the code). The other is the Giga Attack of the Falcon Armor, one game later.
 * Unlike any other armor set, the Ultimate Armor in every game has had several transparent parts, revealing X's inner workings.
 * During the first selling of Rockman X4 for the both PlayStation and Sega Saturn system, Capcom included a Special Limited Pack containing an X constructible model toy, with his Ultimate Armor version. The model was later released on its own, and later re-released with chromed plastic.
 * The Ultimate Armor has the ability to break off in pieces from X's body and re-assemble itself into a flight-capable sled X can ride on top of. Although this has been seen in both the Rockman X manga, official illustrations and can be done with the Mega Armor series model kit, the sled formation is never seen in any video game the armor has appeared in thus far.
 * In the official art depicting the Ultimate Armor's sled configuration, X is depicted wearing his default armor. The manga and Mega Armor Model kit, however, depict a lesser-armored form underneath the pieces of the Ultimate Armor that serves as an armature for the sled pieces.
 * In the manga adaptation of Mega Man X4, X is given, with some amount of hesitation by Dr. Light's hologram, the completed Ultimate Armor instead of the Fourth Armor. The Ultimate Armor is used to mercilessly slaughter Slash Beast, Storm Owl and Magma Dragoon, due to X suffering a mental breakdown as a result of the Repliforce conflict and the murder of Blizzard Buffalo. It later shields itself from the explosion caused as a result of General's sacrifice, which destroys the armor and reveals the Fourth Armor underneath.
 * Zero was originally planned to have his own Ultimate Armor alongside X in X4, but it was replaced with Black Zero. The designer of Zero's Ultimate Armor hinted that his ultimate armor had to do with his connection to Dr. Wily, but stopped himself before he could reveal any more and instead supplied the design.