Samehada

is a mystical sentient sword utilised by the Seven Ninja Swordsmen of the Mist, and regarded as the most terrifying of all the Seven Swordsmen's blades.

History
Passed down from generation to generation since the First Mizukage's era in Kirigakure, Samehada was eventually acquired by Fuguki Suikazan, and at some point, the sword was utilised by Mangetsu Hōzuki in his act of mastering all seven swords of the Seven Swordsmen. Upon Fuguki being killed by his subordinate Kisame Hoshigaki, he took the sword and joined the Seven Ninja Swordsmen. For the duration of Samehada being in his possession, their chakra signatures eventually became identical, and Kisame became regarded as a. When Kisame became a Missing-nin, he took Samehada with him.

During Kisame's initial fight with Killer B, Samehada grew fond of the taste of B's particular chakra and ultimately betrayed Kisame, (who was later revealed to be one of White Zetsu's clone in disguise), by returning some of the chakra it had previously absorbed from B during their battle and even shielding him from his attacks, all while the real Kisame was hiding within Samehada to infiltrate Kumogakure as a spy, before using it to absorb B's chakra when his presence was exposed.

After Kisame's death, Samehada mourns him, not only bestowing the blade with even more life-like characteristics but also standing as a testament to the bond shared between the two. Now in B's possession, Samehada kept five of his Supervibrato Lightning Release Swords within it to better assist him during the events of the Fourth Shinobi World War.

In the anime, fifteen years after the war, Samehada was now back in the possession of Kiri. During the same time, a rebellious group proclaiming themselves the New Seven Ninja Swordsmen stole the seven blades to start a revolution against the modernisation and peaceful era of Kiri, determined to return to the days of the "Bloody Mist". Shizuma Hoshigaki took up Samehada. Despite his high kenjutsu skill, ultimately Shizuma proved too inexperienced with the dangerous blade,which resulted in Samehada taking control over him when he was weakened and therefore causing him to go on a feral rampage. Ultimately, he was defeated and separated from the blade by Kagura Karatachi and Boruto Uzumaki, whereas Samehada calmed down after becoming full and content from all the chakra it ate.

Appearance
Samehada is a large sword, roughly as tall as a full-grown man and comparable in size to the Kubikiribōchō. Though usually wrapped in bandages, Samehada's construction is atypical in that its actual blade is comprised from a series of downward-facing scales running along the entirety of its length until its hilt, at the base of which is a small skull. Samehada grows larger in proportion to the amount of chakra it absorbs, causing its scales to become so long that they ultimately resemble shark fins and its mouth, located at the tip of the blade, to become even more pronounced with visible teeth. Keeping Samehada wrapped in bandages apparently helps to inhibit this growth to a certain extent.

Sentience
Samehada is unique for being a sentient weapon that gains nourishment from the chakra of others and as such, the blade is at its happiest when engorged with chakra that possesses both a distinctive and pleasant flavour. It apparently greatly enjoys Killer B's chakra since, according to Kisame, it tastes like octopus. However, it has shown displeasure towards fire-natured chakra, stating that — according to B — it's far too hot. Being capable of conscious thought, Samehada chooses its own user, an exclusive process that has often resulted in it being thought of as notoriously picky. If someone it disapproves of attempts to wield it, spikes protrude from the handle in order to force them to release their grasp, at which point Samehada will make efforts to return to its chosen owner. To further exemplify it being a sentient being, it was able to mourn Kisame's death.

Abilities
As the blade is made up of scales, it inflicts injuries through shredding or shaving what it comes into contact with, rather than just cutting the object in question. This flaying effect is similar to a shark's skin, hence the sword's name. While it ordinarily remains rigid, Samehada's hilt is able to stretch and bend to great extent, allowing the weapon to be used like a flail. To supplement the blade's offensive capabilities, it is able to extend its scales to spikes, and protrude spikes from its handle. Samehada can also be used in conjuncture with Water Release, leading to the sword glowing with chakra.

Samehada shares a symbiotic relationship with its wielder, similar to that of the kikaichū. Although it continually consumes the chakra of its owner, its largest meals come from fights, where it absorbs the chakra of the opponent by slicing through it, preventing them from performing the technique in question. This is particularly useful when fighting jinchūriki, as Samehada can quickly deplete their large chakra supplies as well as remove their chakra cloaks, illustrated when Killer B was reduced back to Version 1 after initially being in Version 2. B noted that it can near instantly absorb up to six of his tails at once. In fact, although B came into contact with the blade several times in his battle against Kisame, the sword drained nearly all of his chakra, causing the latter to resort solely on Gyūki's. In the anime, it was even capable of "eating" a "Version Two" Tailed Beast Ball. However, it seems to be unable to automatically absorb ambient chakra, as in all instances where it has absorbed chakra are when either the opponent had a visible aura around them or when direct physical contact had already been established. Samehada is even capable of slicing through chakra that is transformed. The more chakra it absorbs, the larger it can become. Due to its voracious appetite, Samehada is drawn to those with large chakra supplies, allowing it to be used as a quasi-sensor. Samehada can produce a mist veil through the wielder's blood. This enables it to absorb the chakra of anyone near through their open wounds.

While the ability to absorb chakra is useful in defeating opponents, it is also beneficial to the user as well. Samehada has the ability to transfer the chakra it has absorbed to the wielder by partially fusing with them, so it can be used to either revitalise the wielders chakra and stamina or instantly heal even fatal injuries. This makes the user of this sword extremely difficult to defeat conventionally. A wielder such as Kisame can take this fusion one step further, by completely merging with Samehada. Doing so causes him to become much more shark-like in appearance, growing fins and webbed hands that allow him to move through water with considerable ease. Kisame also receives some of Samehada's abilities while in this form, such as being able to extend spikes from his body for offence, and absorbing chakra when others come into direct contact with him, as well as the ability to track chakra and avoid sensors. It will fuse with a weakened or inexperienced wielder on its own accord, taking them over and causing them to go on a rampage until they are separated.

Utilised Techniques

 * Bloody Mist Absorption Technique
 * Water Prison Shark Dance Technique