Mariko Yashida is the granddaughter of Ichiro Yashida and daughter of Shingen Yashida, who forms some sort of relationship with Wolverine.
As a child, Mariko led a very sheltered existence. She had been born into one of the wealthiest families in Japan, and as such she would grow to learn of the dangers such a life entailed. Her relationship with her father was a strained one, yet her doting grandfather cared deeply for her, and provided a far stronger parental bond than her father had. The old man went so far as to bring home a playmate for her, Yukio, whom he raised as a foster child after he found her scavenging for food. Mariko's other childhood companion came in the form of Kenuichio Harada, a boy with whom she shared a martial rivalry: Mariko with knives, and Harada with a bow.
In her adult years, Mariko tried to offer comfort to her ailing grandfather as his body slowly failed him, although it was she who also needed the comfort as his death was to be a loss keenly felt. One night Yukio returned from abroad with a "caveman" in tow, the man Logan her grandfather had been seeking for some time. Mariko disapproved of the stranger at first, but could only look on from a distance as he was taken to see her grandfather. Later that night the old man passed away, and Mariko attempted to throw herself from a parapet in despair, until Logan intervened and prevented her from committing suicide.
In the coming days Mariko found out that it was she, not her father, who had been named as sole inheritor in her grandfather's will. This put her childhood friends on alert, and so on the day of the funeral Yukio stayed close by while Harada watched silently from nearby rooftops with his bow close at hand. Their fears were answered when Yakuza thugs who were disguised as Japanese priests attempted to kidnap Mariko, only to be blocked by the combined efforts of Harada, Yukio, and Logan. She found herself being led away from the scene by the Canadian who fended off multiple attacks as they made their escape.
In the following days the pair fled south, with Logan acting as protector while Mariko was the guide. They made their way to a remote house owned by her family where they finally stopped to rest. The pair were bonding and happy to be in each other's company. Logan and Mariko then hide in Yashida's house down south and as they start to fall for each other, Logan reveals moments from his past such as the war and Jean. However, the happiness was short-lived; Yakuza thugs eventually tracked down their whereabouts and kidnapped Mariko while Logan was sleeping. Awakened by the sound of her screams, Logan tried to stop them, but could only grab one as their car sped away.
Mariko was taken before her father, who explained to her that the inheritance that had skipped a generation was an unforeseen problem. She tried to leave, but his men blocked her escape. Her life was now in the balance and there was nowhere left to run. Harada however, had learned of her presence and staged a rescue mission along with his ninja clan.
Mariko was taken to a Yashida complex where her grandfather had made some significant steps in fomenting his empire. She soon found that she had again become a captive in a tangled web of intrigue, with Logan, who had tracked her there and was now captured himself, Viper her grandfather's former nurse, and Harada apparently doing the bidding of Viper. Viper acknowledged that Logan's presence was required for his power to be extracted, and the engine of this extraction was a construct of adamantium with the appearance of a samurai warrior.
A fight erupted when the behemoth moved to begin its task, and Mariko leapt to defend him, thus causing the warrior to destroy Logan's restraints. Harada also turned on Viper and the Silver Samurai, and died trying to fight it off. Yukio, who had followed Logan, also joined the battle. After a lengthy confrontation Logan severed the head of the adamantium warrior, and much to Mariko's horror revealed her grandfather still alive within. She was distraught in the knowledge that the loving man she once knew had become the monster she saw before her, preserved by the suit's life support system and intent on killing her love. Mariko stabs her grandfather's head with Logan's broken claws, giving Logan the opportunity to finish him off. Logan, Mariko and Yukio then watch as Yashida and the armor tumbled over the side of the building to their final destruction below.
The next morning, Mariko is appointed the new CEO and began putting the Yashida business empire back together. She now had a new destiny before her, and she knew that Logan had his own. They said their goodbyes and parted company, Mariko providing a private jet to take him anywhere he needed to go, and with Yukio as his bodyguard.
