Katana is a fictional character in the DC Universe of comics. Naming herself for the soul-claimingkatana she carries, Tatsu Yamashiro of Japan became a member of the Outsiders and the Justice League.

Tatsu was an average japanese girl, save for her proficency in the martial arts. Two brothers, Maseo and Takeo Yamashiro, both proclaimed their love for her. While she liked both, she chose Maeso. This angered Takeo, and refused to attend the couple's wedding. By this time, he had joined the Yakuza, recieving a large dragon tattoo accross his chest to mark himself as such. As a result, his family disowned him.

After the death's of Tatsu's parents, (cause unknown) she and Takeo started a family of their own, and she gave birth to twins, Yuki and Reiko.

Meanwhile, Takeo rose in rank of the Yakuza, and one of his exotic tastes included ancient weapons. He was presented with a pair of matched swords by General Karnz, one of which Takeo favored due to its mystical properties, which would come to be known as the Soultaker.

One night, Takeo took both swords to the Yamashiro residence, tossing the non-powered sword to his brother and demanding he duel for Tatsu, whom he quickly struck down. In the course of the fight, Takeo accidently started a fire, and while distracted by his children, Maseo was slain with the Soultaker.

Tatsu arose just in time to see her husband die, and engaged Takeo, gaining the upper hand and disarming him. When she attempted to go after her children, she heard her husband's voice telling her to turn back- coming from the sword. She listened, and watched as her house burned.

She then began her quest for vengence, killing General Karnz in Markovia, where she met up with the Batman, and joined his new team of The Outsiders.

The Soultaker, along with its non-powered twin, was forged in the 14th century by Muramasa, who's swords were said to be cursed and make those who were evil commit evil acts. It sometimes takes the souls of those it kills, sotring them inside the sword, where they can engage in limited communication with whoever wields it. These souls can be reincarnated by the means of a sacred ritual , under which they serve their summoner, even if it is against their will.