Kage Kage no Mi

The Kage Kage no Mi is a Paramecia type Devil Fruit that gives the user the ability to manifest and control shadows as a tangible physical form. "Kage" means shadow. In the Viz Manga, it is called the Shadow-Shadow Fruit. It was eaten by the former Shichibukai member, Gekko Moriah. Its powers were first noticed on Brook when he first dined with the Straw Hats.

Strengths


The first and foremost strength of the fruit, as demonstrated by Moriah, is that its user is able to manifest shadows into a physical form. With this power, the user is able to grab hold of their victim's shadow. They are then able to cut it with a pair of scissors as if it were a cloth. With the shadow, they are then able to place it into a lifeless corpse in order to create a zombie minion. The size of the shadow itself doesn't have to be in proportion with the corpse's own in order to revive it, as seen when Moriah reanimated Oars' colossal corpse using Luffy's shadow. The minion that is created retains the mannerisms and abilities of the victim. The minion, however, is only as strong as the body it is composed of. The minion by itself also doesn't inherit any Devil Fruit powers of the original owner of the shadow. Though the minion doesn't inherit any Devil Fruit powers, the Kage Kage no Mi user can manipulate the minion's shadow so that its body can simulate the body changing abilities, such as those of some Paramecia Devil Fruit users.



As for the original owner of the shadow, they will enter a two day coma once their shadow is separated from them. The Devil Fruit user can use this effect to their advantage in battle as the original owner is completely defenseless until they wake up from their coma or are woken up. The original owner of the shadow is then forced to remain in darkness as they will vaporize if hit by sunlight. Being unable to exist in light, the original owner is also unable to cast any sort of reflection and is also unable to be photographed.

The Devil Fruit user also has full control on whether or not the shadows return to their original owners. Simply beating the user, or even killing them, will not return the shadows the user has stolen. The user must willfully say that a shadow should return to its master in order for it to be fully returned.

The user is also able manifest their own shadow as a semi-liquid physical form. They are then able to control their shadow and make it fight for them in their stead. Their shadow, as a physical manifestation, is a being of strengths similar to that of a Logia Devil Fruit user as their shadow, in that state, is impervious to damage. It is also able to change shape and size depending on the user's wishes. The user is also able to switch places with their shadow in order to get to different places. The moment when the user switches places with their shadow can also be used to dodge attacks in a similar fashion to when a Logia type Devil Fruit user transforms into their element in order to dodge an attack.

The most powerful strength of the fruit is that the user can use the shadows they implanted into their zombie minions into themselves to power themselves up. This power up can be devastating depending on the number of shadows they implanted, and can ultimately cause the user to swell dramatically in size.

As seen during the Whitebeard Vs. Marine war, the Kage Kage no Mi is especially useful in war-like conditions; the bodies of the fallen soldiers in the battlefield making for easy zombification.

Weaknesses
One of the major weaknesses of the fruit is that the user can only fully control minions whose shadows come from owners who are relatively weaker than them. Minions with shadows that come from relatively strong owners are harder to control. One example of this happening is when a Dog Penguin zombie with Sanji's shadow, Inuppe, fought against the other zombies to protect Nami. Despite this, no matter how strong the shadow is, it will soon forget its memories of its original owner and obey Gekko Moriah completely.

If a zombie given a shadow from this fruit's power is fed salt, it will cause the shadow to return to its original owner. This is because salt is an element of the sea (salt water), which takes away Devil Fruit powers. The amount of salt required to extract a shadow from the zombie is proportional to the said zombie's size, as Oars was immune to a salt pellet shot by Usopp. A shadow will also return to its original owner if the corpse housing the shadow is completely destroyed. It is hinted at the fact that the death of the original owner has no effect on the shadow since Hogback stated that once it's extracted, it is best to get rid of the owner. In particular, a Fishman who knows this Devil Fruit's fatal weakness becomes a serious threat to the user.

Another notable weakness is since the user normally relies on shadows in order to be able to do anything with their powers, depriving them access to shadows, including their own shadow, can greatly disable the fruit's functionality, as seen when Moria's shadow was separated from him when Doflamingo came to eliminate him.

The most major weakness of the fruit, however, is that the shadows that were created by the user's powers can be used against them. After a zombie minion is purified, the shadow that is freed can be caught by anyone since it is still temporarily in a tangible state until properly reunited with its original owner. They can then implant that shadow into themselves or into an ally. Additionally, the user appears to have no way of keeping track of the shadows that they extract from their victims. An example of this was when Luffy, in Nightmare mode, came out to confront Moriah, the Shichibukai actually thought that Luffy's new form was a result of shape-shifting powers, not realizing his part that led to Luffy becoming that strong until much later. If the person is still conscious, they can then gain the abilities of the shadow's original owner and become stronger. More than one shadow also can be implanted into them thus their strength can be multiplied by the number of shadows implanted into them. However, because the shadow that is implanted into a living person is not of the same soul, the shadow will only stay in their body for ten minutes. Afterwards, the shadow will return to its original owner. Also, the number of shadows that can be implanted into a person is somewhat limited to how strong the person's spirit is. If the person's spirit is weak, they'll lose consciousness and the effects of the shadows will go down the drain. For most regular people, two or three shadows is the limit for them.

Moria also has yet to demonstrate being able to utilize, in any way, shadows that had been cast by inanimate objects, hinting that his power only affects those belonging to living beings, since he was never seen being able to revive zombies using shadows that belonged to anything other than living people.

Other than that, the user is also affected by the standard Devil Fruit weaknesses.

Usage


The fruit's bestowed powers, as used by Moriah, have been used mostly to create a large number of zombies in Thriller Bark. With it, he has been able to steal various shadows from various people who unfortunately stumble across his island. With the help of Hogback's surgical ability to create all sorts of creatures, and a large freezer filled with tons of corpses, Moriah has been able to create a large army of the dead.

Moriah is also able to use the powers in battle in a manner suiting his personal motto. Moriah is able to manifest his shadow into a dark semi-liquid like silhouette figure resembling himself. This being is capable of being impervious against conventional attacks. This being is also capable of splitting itself into smaller bat-like shapes. Overall, Moriah mostly uses his shadow to both attack enemies and protect himself without personally doing anything.

Moriah can also use the fruit's powers to switch with his own shadow. This can come in useful, either to travel long distances or to escape from enemy attacks. Since his zombie minions don't inherit Devil Fruit abilities from the shadows animating them, Moriah can also aid his zombie minions in the execution of some of their techniques by implanting his shadow into theirs.

The most devastating thing Moriah can do with the fruit's powers is to empower himself with the shadows he uses to animate his zombie minions, absorbing both power and skill, assimilating them into his own. A person that had a shadow infused into them would also experience similar effects (first side-effects often include an area around their eyes darkening in color), and the more shadows they absorb, the more power they amass. Of course, the number of shadows that they can take in at any given time all depends on their willpower. Apparently, if a person absorbs more than one shadow at once, the excess effect can actually cause their bodies to change in appearance. This often causes them to grow in size to epic proportions, as was in the case of Luffy in his Nightmare Form, and Moria after using Shadow's Asgard.

The named techniques that are used by Moriah are as follows:


 * Doppelman (影法師（ドッペルマン）): the name of the dark silhouette-like figure Moriah made using his own shadow. With this "shadow clone", Moriah can use it to fight in his stead. Its name is derived from doppelgänger. This was first seen being used against Luffy. He can also switch places with it at will.


 * Brick Bat (欠片蝙蝠（ブリック・バット）): Moriah transforms his "shadow clone", Doppelman, into a myriad of balls. These balls then turn into a swarm of bats that can attack an opponent. After being used, the bats can merge back together to reform Doppelman. This was first seen being used against Luffy.
 * Black Box (影箱（ブラック・ボックス）): While in his form upgraded by Shadow's Asgard, Moriah turns his shadow, made even larger by his Shadow's Asgard colossal form, into several Brick Bats. He then has them transform and completely encase an opponent in a black box made out of solidified shadows. With his opponent encased in the box, Moriah is then capable of smashing the opponent with either his hands or feet. This was first seen being used against Luffy in his Gear Second form.


 * Kage Kakumei (影革命): Moriah implants his shadow into a victim. With it inside, he is able to manipulate the shape of the victim's shadow. When the shadow's shape is changed, the victim's body will be changed too. This is first seen being used on Oars. Moriah is able to do this because of the general rule about shadows. It is common knowledge that a shadow will always comply with the body casting it. Because of that, the shadow and the body are always the same shape. By changing the shape of the body's shadow with Moriah's powers, the body is forced to match the shape of the shadow. In effect, it's the reverse of a shadow changing shape to match with the body casting it because it is the body that is now transforming to match the shape of the shadow it is casting. It's basically the reverse of shadow puppetry. In the Viz Manga, this is called Shadow Revolution.
 * Oars Ball (オーズ・ボール): Using Kage Kakumei on Oars' shadow, Moriah changes Oars into a gigantic ball to crush his opponents. This was first seen being used against the Straw Hats and Brook. However, the attack's power wasn't shown because Oars asked Moriah to finish the Straw Hats himself.


 * Kagemusha (影武者): a technique in which Moriah can swap places with Doppelman at any time, allowing Moriah to practice a form of teleportation of sorts, making it very hard to hit him. This was properly shown and explained later when Robin attempted to snap his neck with four gigantic arms. This technique's name comes from the term used in Japanese to refer to an impersonator.


 * Shadow's Asgard (影の集合地（シャドーズ・アスガルド）): A supplementary technique in which Moriah empowers himself with the shadows he has deprived by devouring them. In doing so, his size and physical strength are increased in proportion to the amount of shadows he has absorbed. On Thriller Back, he accomplished this by using his own shadow to impale and remove the shadows of his zombie minions, absorbing 1,000 shadows into himself. The large number of shadows increased his proportions to rival that of Oars, and gave him physical strength sufficient to split Thriller Bark in half with a single attack. In this form, Moriah's neck bloated to extreme proportions, similar to how a gecko puffs up its throat when threatened. His horns also became longer and his hair became spike-like in manner. His arms also became very huge while his legs became longer compared to their original stubby appearance. Because of his body proportions in this form, Moriah was forced to walk on all fours, further referencing a gecko. When used against Jinbe, Moriah took in a much smaller amount of shadows (around a dozen at most), which merely doubled his height without much change in his proportions or appearance. The drawback to this technique is that Moriah gains size at the cost of speed. When used against Luffy, he was practically unable to land a hit when Luffy was in Gear Second. In addition to losing speed, Moriah has trouble controlling large amounts of shadows inside his own body, and is prone to regurgitate them in small amounts if struck hard enough. This decreases his overall power, as the shadows return to their original owners when liberated. This technique's name comes from Asgard, the Norse mythological city of the gods. In the Viz Manga, this is called Shadows Asgard.


 * Tsuno-Tokage (角刀影): Gathering his shadow together, Moriah shoots out a large shadow spear at an opponent. The tip of this spear resembles a horned lizard. The Kanji for the move reads Horn Blade Shadow; however, pronunciation-wise, it resembles the Japanese word for Horned Lizard, thus making the name a pun. This was first seen being used against Little Oars Jr.. In the Viz Manga and FUNimation subs, this is called Spiky Shadow Lizard.

Though unknown on how it was done, Moriah also displayed the ability to literally disappear, demonstrated when he was about to be killed by Doflamingo and the Pacifistas in the aftermath of the Battle of Marineford. Even though the scene wasn't seen, Doflamingo said Moriah had disappeared and commented that he had never thought the Kage Kage no Mi would have this ability. However, this could simply be the "Kagemusha", swapping places with his shadow, seen to be detached from him throughout the course of the war, it was probably in another place so he could swap with its place and quickly call his shadow back; Doflamingo could be unaware of this ability.

Nightmare Luffy


The fruit's powers have also been used outside of Moriah's own will by some of Moriah's victims. They learned how to harness the fruit's ability to make shadows tangible for their own benefit against Moriah himself. Over the years, while trying desperately to recover their own shadows, they learned that they could capture shadows that had been purified from Moriah's zombie minions. They could then put the captured shadows into themselves and gain the abilities of the shadow for a short period of time. Using this knowledge, they were able to imbue Luffy with a hundred shadows and turn him into Nightmare Luffy.

Nightmare Luffy (ナイトメア•ルフィ) was Luffy's form after he was greatly powered up by one hundred shadows implanted into him. With Luffy's strong spirit, he was able to contain one hundred shadows within him when most normal people could only contain two or three. In this form, Luffy was several times bigger than his normal self and his skin turned completely blue. He was roughly the same size as Moriah and his body was similar to Chopper in Heavy Point. Luffy also talked differently, losing his usual carefree tone and instead speaking with a grim seriousness. While in this form, Luffy was capable of using the combined strength and skills of the shadows within him. With this strength, Luffy was even capable of stopping a giant Gomu Gomu no Rifle attack delivered by Oars with one hand and of delivering massive attacks onto the zombie behemoth. Because one of the shadows belonged to a swordsman, Luffy also gained the ability of fighting with swords, something he never knew before. This form however only lasted for ten minutes. After that, all of the shadows within Luffy returned to their original owners. He also appears to be able to move at an incredible speed, having safely snatched up both Nami and Usopp away from a rampaging Oars and it was only when Luffy made his presence known did Oars and Moria learned about it.

In One Piece Green: Secret Pieces were revealed early concepts of Nightmare Luffy, one of them was a "polite and serious" Luffy.

In the game Unlimited Cruise, Luffy, in this form, has also displayed other abilities to compliment those seen from both anime and manga. Such abilities include being able to breath fireballs after drinking some liquid from a calabash, and shooting out multiple flaming arrows at a considerable range with a longbow.

Trivia

 * The way Moriah steals shadows from his victims, by cutting them off like pieces of clothing from their feet, resembles the concept of Peter Pan's own cloth-like shadow.
 * The way a zombie is purified, by making them eat salt to negate the Kage Kage no Mi's powers, resembles a common belief in Japanese folklore. The belief is that one can purify an evil spirit, like a zombie, by making them eat salt, which is believed to have holy properties.
 * In the anime, a shadow zombie will share the same Seiyu as the shadow's previous owner. For example, Oars sounds like Luffy. In the manga, it is stated that the shadow gets a new voice as well as a new body.
 * Although Moriah's victims vaporize when they lose their shadow and are exposed to sunlight, Moriah is able to detach his shadow in the sun.