Excaliburn

"That...is not a sword."

- A common point made about Excaliburn's appearance Excaliburn (縁九巣狩り羽庵(エクスカリバーン), Ekusukaribān; Literally Meaning "Nine Fateful Dens, Hunting Rabbit's Retreat"), also known as Legendary Tool of the Gods (神々の伝奇器, Kamigami no Denkigu) and Blade of Redemption (遡求の剣, Sokyū no Tsurugi), is, as its titles imply, a legendary magical artifact, known as an all-powerful weapon once used to decimate armies. However, it fell into obscurity after being lost in the aftermath of a vicious war thousands of years ago.

It has since become the equivlant of a myth, since no one could ever find Excaliburn again, leading to many legends and tales about it, the most common being that Excaliburn is a "Holy Sword" (聖剣, Seiken), a blade forged by the heavens themselves, when in reality, it is a much more complex tool, possessing sentience and its own way of thinking.