Artemis's Katana was passed down to her by her mother, who has distant relations to a shinobi group from Japan.
The sword has a hilt wrapped in the finest leather from the 14th century. There is an emerald embedded in the bottom of the hilt. The metal of the blade was forged over five days of hard craftsmanship. The only thing that would break it is a well-placed blow from a hammer of any kind. The sheath is cleverly designed to make one believe there is nothing special about the blade within.
The sword was crafted in use for assassination, and passed down through generations of ninjas. It was used to fight Samurai during the final days of ninjas. Eventually, although still passed down, it never shed blood since. Until Artemis came to be in possession of it.
By mid-2016, Artemis has come to learn how to use magic. She is able to turn the blade orange, initiating her use of Fire Magic. When she does this, it unleashes her Special Attack: The Blade of Grief.