Shinentō

The Shinentō (深淵刀, Literally Meaning: Abyss Sword) are two, said to be an ancient artifacts currently belonging to Kuro Kazuto.

History
The Shinentō has existed for centuries, originally just two ordinary swords. When a monk was creating a piece of armor for a Daimyō, he decided he no longer wanted to give away his creation. He had poured his pride and soul into the armor and thought it would better suit itself in his possession. He knew the Daimyō would never accept this so he took action, the monk devised a plan to kill the Daimyō, so he would no longer have to give the armor away.

And so he did, he went through with his plan and killed the Daimyō, assassinating him with two swords hidden from behind his back. The Daimyō's vengeful soul shattered into two, getting absorbed by both the swords and the armor, the armor was later named the Shinengai.

The monk later tried to wear the armor, trying it out once again now that it was officially his for sure. As he was putting on the armor, he couldn't help but feel a dark presence, a spiteful, enraged presence. He started to feel the armor tighten around him, slowly squeezing him, he couldn't take off the armor, it was too tight. His heart started to beep faster than it had ever before, adrenaline rushed through him, but it was too late. The armor had suffocated and killed him. It turns out the Daimyō soul had been transferred into the armor, and so it sat, next to the two bloodied swords that killed the man.

For hundreds of years, the swords were passed between owners, each being killed until it settled on Kuro Kazuto, the current owner of the Shinentō. The Shinentō finally thought it found an owner worthy of its mighty abilities.

Appearance
The Shinentō are two large blades, heavy-set and jagged. The Shinentō are black and glowing red in coloring, the red being most of the blade and the black being mostly the base. It has a chain wrapping around the base of the blade, symbolizing the Daimyō being chained to the sword.

Sentience
The Shinentō are unique swords, unlike many blades, the Shinentō is sentient. Seen as it enjoys the blood of users it disapproves of to regenerate, as such, the swords have a specific blood type that it in enjoys most. The Shinentō's favorite type of blood is AB, it was said to have a sweet, pleasant flavoring to it. This shows that the Shinentō can actually think.

Abilities
The Shinentō has a variety of abilities, giving the user an edge in combat in most situations.

Like the weapons in use by the Seven Ninja Swordsmen of the Mist, these swords automatically regenerate from blood. The swords do this through reforming itself from iron harvested from blood, half of the blade was once seen completely severed, and completely unusable, the user fought on in a rampage, letting his sword taste blood. In mere moments, almost instantaneously, the same iron started to reform and regenerate to the swords' original state using the blood spilled in battle.

A particular seal was tied to the swords, attaching it to its corresponding armor, the Shinengai, so it may never be lost from the true owner. This can only be used when the user is in possession of the armor but can be summoned at will so the swords can never fall into the wrong hands.