Katana 's Sword which has the ability to take the soul of those it slays, sending it to a dimension that can only be traveled to through the sword. It is capable of deflecting bullets and is durable enough to resist extreme heat and other types of attacks. The skein is as sharp as a fine monomolecular edge, sharp enough to cut even the dilustel comprising Major Force's unbreakable skin.
She can communicate with the sword and use it as a tracking device to track anything she wants. Those killed can be taken out of the dimension to serve her will as ghostly vanguards but only with a certain incantation and in the right setting. Katana's honor is with the sword and she will do anything to protect it.
In The New 52, Katana believes the Soultaker to hold the soul of her dead husband, who communicates with her, learning information from the souls she kills. It is also said that the blade is a something called a sword totem belonging to the Outsiders supposedly bestowing its wielder immortality and enlightenment.
In other media
In Batman: The Brave and The Bold, there was a animated version of Soultaker that Katana used, which has appeared on several episodes.
In DC Superhero Girls, an animated recasting of various imprint characters in a highschool setting. Katana wields her magical blade with the same mastery and finesse as her print counterpart. The reboot of said series adds the element of One Hit K.O. to her sword by projecting immaterial slashing motions that remove the souls of those it cuts and transfers it to Soultaker afterwards.