Born into a powerful yakuza family, Mariko met Wolverine in Japan during the first visit of the group to the island. Logan felt attracted by her, possibly due to the difference of their natures, and she felt attracted by him as well, but had to reject him due to her father, who had given his hand to another man for strategic interests. Not very happy about it, Wolverine made a new trip to Japan, just to discover that she has been beaten by her new husband. The news turned him mad, but Lord Shingen used his katana and ninjas to beat him up, leaving him almost dead in the streets. There, he got saved by Yuriko, a ronin who worked in the streets. Wolverine managed to kill Lord Yashida and the husband of his girlfriend, and they promised in marriage, but when Mariko learned the truth about her family business, felt unworthy of marrying Logan, breaking the compromise and becoming head of the Clan, trying to make things better, against the will of his cousin and otherwise successor, the Silver Samurai. During that time, they kept their relationship, and Mariko took care of Logan's adoptive daughter, but as head of the clan, he was target to the other families.

To stop a war between clans she was forced to cut one of her fingers, according to tradition, but was given a poisoned daga and died. Lord Shingen's katana, her wedding gift for Logan, was then returned by him to the clan.