Ryūbōden

The Ryūbōden (竜宝殿 Dragon's Treasure House; Viz "Cave of the Dragon") is the blade currently possessed by Shūgetsu Hōzuki. With it, he aspires to be one of the new generation of the, considering that his relative, Suigetsu Hōzuki, desires all the former blades for himself.

History
Prior to acclaiming it, the sword was forged by the great, Hakuhei Ryūmeijin, a man who had sold his blades to both and  alike. At this point in time, the world was still in the, and thus, sales were extremely high for the swordsmith. He was approached by a Shinobi of the 's predecessors, and bought the sword off of him for a plentiful sum of money, considering the effort that he went to forge the sword.

Afterwards, the sword's name was written in infamy considering the number of people it killed. It was also rumored that the sword itself was possessed, causing the individuals who wielded it to become bloodthirsty tyrants. Though the truth of this claim isn't known, considering that individuals of Kirigakure were always regarded as such. It also gave the individuals monstrous abilities, but in exchange, waned their lifespan until their death.

Eventually, after having been sealed away in an unknown area for a considerable period of time, Shūgetsu was able to retrieve it after escaping from his family home. As of now, he wields the blade to further advance his skills, and escape from his inferiority complex.

Appearance
The Ryūbōden takes the appearance of a very large sword, with a similar shape to that of a -like blade. However, this is only the initial shape of the blade. As more details are noticed, one is able to see that the edge of the blade has a constant curving pattern, which appears akin to that of a. Aside from these features, Ryūbōden has a noticeably large hilt, which is dark grey in color, and holds a spiked ring-like protrusion at the end of it. Complementing this is the slightly darker cross-guard, which appears as a draconic face with folded wing-like protrusions coming out from behind the head, along with two on its left and right respectively. Notably, when the blade's ability is conjured, the face's eyes light up a bright blue, along with chakra flowing down the blade in the shape of a serpentine dragon.

Abilities
Ryūbōden's initial characteristics are that of extreme natural sharpness and the ability to cut through innumerable substances with absolute ease. This is made possible through the unique edge of the blade, which allows the force of Shūgetsu's swings to make impact at various points, allowing for a number of different cuts at various positions despite a supposed single attack. However, it is also proven that the blade is considerably heavy, and that he tires out quickly using it unless he employs another technique to boost his physical strength.

However, the true ability of the blade comes into play whenever Shūgetsu employs Chakra Flow. Upon doing so, Ryūbōden's internal stores of chakra are released and magnify his own chakra that is flowed, which allows for the draconic-like aura of the blade to appear whenever chakra flow is used on the blade. Revealed later to Shūgetsu through a specific scroll; Ryūbōden actually holds an enormous level of internal chakra within it, forged through an unorthodox, forbidding swordsmith technique of Hakuhei's invention, presumably utilizing actual to do so. Nonetheless, this chakra immediately resonates with that of the user, causing the various personalities to subconsciously be ingrained into Shūgetsu for a brief period of time. This allows him to gain a variety of stances and forms that have been antiquated for a number of centuries.

The secondary ability of Ryūbōden is the ability for its internal chakra to be fused with the physical being of its wielder, which in this case is Shūgetsu. Upon the fusion, the chakra of the blade surrounds Shūgetsu in a spherical shape. This then compresses surrounding him, until eventually through it completely seeps into his water-based body. As a result, he gains a dramatically different appearance, somewhat similar to the likes of Samehada's fusion appearance. His hair darkens to a light purple color, and becomes chest-length, along with his skin becoming a light turquoise-esque, and him having various fish-like structures on his body including fin-like ears, uniquely shaped eyes, and protruded nails. His physical abilities enhance tremendously in this form, allowing him to utilize the blade with terrifying ease. From what is noted, his abilities transcend to that of a -level combatant, but thanks to increased chakra expenditure, he quickly reverts back to his initial form, with the chakra returning to the blade. Furthermore, his own hiden techniques are enhanced prominently; this is best demonstrated with the ability to use his nails as projectiles and his hair as a whip-like structure, indicating at a natural connection between the Hōzuki Clan and the weapon. Whether this was intentional on Hakuhei's part is not known.