Blades of the Samurai (5e Equipment)
From D&D Wiki
These jet black blades (katana and wakizashi or shortsword) with a black cloth wrapped around where the hilt and guard should be, have the soul of the previous Samurai Warrior inside.
Legend of the Blades: While his father was in battle, Ichi (a small 10 year old boy), came to beg for his fathers life. When the opposing samurai slashed Ichi's father across the belly, his blade ran across Ichi's eyes, blinding him for life. To avenge his father, the local sword-master taught Ichi how to use his fathers daisho in a way like no other. This never-before-seen teaching also granted Ichi with the capability to see through the usage of magics.
You gain a +3 bonus to attack and damage rolls with both these magical weapons, and you can use either your Strength or Dexterity modifier on attack and damage rolls with it. On a hit, the katana deals an additional 1d8 slashing damage and the wakizashi or shortsword deals an additional 1d6 piercing damage. This weapon has 6 charges that it can expend and replenishes 1d4 + 2 charges daily at dawn.
Attunement: When you attune to this weapon you lose all your sight, but when you do a strip of black cloth will come off of the hilt and magically slide up your arm and tie itself around your head and over your eyes.
Samurai's Might: By expending 2 charges, the owner of the katana can release the might of a samurai. Letting the might converge upon the blade, the user can quickly draw their weapon as an action, releasing a downward strike that causes the necrotic energy of the weapon to be expelled forward in wave of foul energy. Any creature within this 5-foot wide, 30-foot long line must make a DC 18 Dexterity saving throw. A target that fails its saving throw takes 5d10 necrotic damage, or half as much on a success. The expenditure of 1 extra charge will raise the saving throw DC by 1 for each charge spent.
Samurai's Fury: By expending 4 charges, the owner can utilize a deadly array of attacks. While held within the sheath, the user can channel the echo's of the samurai's rage into the katana blade and expend their action, bonus action, and all their movement to take the Attack action but make double the amount of attacks they would regularly make. The user explodes forth in a flurry of one-handed slashes that ultimately ends with the owner sheathing the blade.