

Deconstructed and Defied later by a certain Ultimate Blacksmith.The oldest is also said to be in the strongest category of swords, and is likely to be much more evil. It's also the youngest, and thus weakest, of three swords of the same class by its forger. It is not sentient, nor does it ever "communicate" in any way- we only have Zoro's reactions and sense to go on. Occasionally it delivers a serious blow when Zoro tries to hold back, like on Whiskey Peak. It encourages the owner to seek conflict and kill, but Zoro was able to overpower it. In My-HiME, Mikoto's sword Miroku is an aspect of a very malevolent demonic entity, and it rarely ever leaves her sight because Mikoto's family had trained her to use it ever since she was little, and it and the pendant she wears possess mind-controlling powers.

Then it showed up in Negima! Magister Negi Magi - not played for comedy (much).
#Empire of sin best weapons movie

Some Zanpakutōs count as well, since not every Soul Reaper is a good person.

In an anime-filler-arc-only appearance there are the Bakkōtō swords that - unlike Zanpakutō who are borne of their users' souls - are more akin to parasites that will become increasingly powerful with their wielder, but also devour their user eventually.Because they are so common they also vary much more in how they are evil. The sword and mace are the only medieval weapons that cannot serve any purpose except war. Most other weapons have a peaceful purpose: bows and spears for hunting, hammers for hitting nails, axes for chopping wood. A dagger is insidious, an axe encourages brutality, staffs are subtle and sophisticated in their corruption. The "personality" of the evil weapon often varies according to the traits associated with it. If It Was a Gift - do not trust the giver thereafter. Some may be Forged by the Gods - but not by any of the nice ones. With some, it's the material they were made of, and some were corrupted by evil deeds done with them, even worse than the usual cruelty of the battlefield. Some are imbued with the evil of their maker, some indeed, are the Soul Jar of an evil human, if not something even worse. How did they come to be like that? Some were deliberately enchanted, or rather cursed.
