This is the mystical sword utilized by the Seven Ninja Swordsmen of the Mist, regarded as the most terrifying out of all their blades. Samehada is unique for being a sentient weapon that gains nourishment from the Physical & Spiritual energy of others and shares a symbiotic relationship with its wielder. Samehada usually chooses its own user, but this has been changed such that Samehada views you as its one and only wielder. If someone else attempts to wield it without your permission, spikes will protrude from the handle to force them to release their grasp. If that's not enough, it will start draining them of their Physical & Spiritual energy at an increasing rate until they either let go or die, at which point Samehada will return to you.
Because of this bond, Samehada will constantly consume your Physical & Spiritual energy (though never enough to majorly hinder you). Its largest meals come from fights, where it absorbs the Physical & Spiritual energy of the opponent by slicing through them, stopping them from performing techniques that require such energies. It can also slice through techniques made of such energies and consume them. Due to its voracious appetite, Samehada is able to sense such energies and communicate when it senses them to you. It can also produce a mist veil through your blood. This enables it to absorb the chakra of anyone nearby through their open wounds. While the ability to absorb chakra is useful in defeating opponents, it is even more beneficial to you because of your bond with Samehada. Any energies it absorbs can be transferred to you, revitalizing your Physical & Spiritual energies, stamina, or even instantly healing fatal injuries.
Samehada's construction is atypical in that its actual blade is comprised of a series of downward-facing scales running along the entirety of its length until its hilt. As such, it inflicts injuries through shredding or shaving what it comes into contact with, rather than just cutting the object in question. Ordinarily, Samehada remains rigid, appearing as a large Greatsword covered in scales. Its hilt is able to stretch and bend to a 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. Samehada can also be used in conjunction with your physical and spiritual energy, leading to the sword glowing with energy and enhancing its various abilities. Samehada will grow larger in proportion to the amount of energy 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. Usually, its bandages help to inhibit this growth, but you will actually have full control of this transformation, able to choose its state as long as the proper energy is given for the larger forms.
Your bond with Samehada can be taken one step further by temporarily merging with it. You can receive some of Samehada's abilities, such as being able to extend spikes from your body and absorbing the physical & spiritual energies when others come into direct contact with you, as well as the ability to track such energies and avoid the senses of others.