- "I am willing to die for my ideals. Can you say the same?"
- —Mamushi to Lo Wang.
Shiho Yamamoto was born to a single mother. After faking her death in a fire, that took the life of her mother, she got in touch with her father, Jairo Yamaguchi, the Oyabun of the Yakuza. Although at first Mamushi tries to pretend to be a loving daughter, she ends her act, when her father disregards the possibility of her taking over Yakuza.
In order to impress her father and show him, that Mamushi can become a great leader, she overhauls every single business unit from gambling to prostitution, turning them massive cash waterfalls. Still, this doesn't please her father and Mamushi decides to kill him and take the leadership of Yakuza by force.
After killing her father and taking control over Yakuza, she consolidated her power by marrying his top lieutenant, Hiro Mori. This helped to keep the police, the press and the gangs off her back. Nine months later, she conceives a daughter, Kazuko with her husband Hiro. Sometime later, she kills Hiro and completely takes over Yakuza.
During the Collision, Mamushi leadership was tested by various smaller gangs, who wanted to take Yakuza from her hands. Thus she waged war with any opposition, she came across. Mamushi also started selling Shade all around Onishima. She was then approached by Mezu, who proposed a business arrangement. If Mamushi lets Mezu to conceive a child with her daughter Kazuko, he will give her enough power to destroy all opposition.
Although hesitant at first, Mamushi accepts Mezu's offer and lets him to violate his daughter. This leads to Kazuko giving birth to a crossbreed daughter, Kamiko. Meanwhile Kazuko herself dies due birth complications. Mamushi is at first enraged by this outcome, but in the end accepts it. When Kamiko shows interest in working at Zilla Labs, Mamushi is completely against this idea, not wanting to deal with Zilla. But when Kamiko suggests, that she could spy for Yakuza and let them take over Zilla Enterprises from the inside, Mamushi complies as Mezu begins showing lots of interest in Zilla's experiments.
Shadow Warrior 2
Mamushi Heika is a leader of the one of the most powerful Yakuza groups in this region of Japan. First time player meet her in her office, where she is looking for someone to save Kamiko. After events of that mission she moves to office located above the Laundry near Wang Cave on Dragon Mountain.
After ZillaCorps attacks this region,she relocates back to her large office, where player meets her in quest to recover Oyabun's weapon. When player reaches her, she kneels before desk. During discussion with Lo Wang she stabs her abdomen with this sword and dies due to blood loss.
Mamushi Heika is a ruthless leader that controls Yakuza with an iron fist. She expects total loyalty from her subjects. In order to gain power, Mamushi can go to great lengths, even giving her daughter to an Ancient to be raped. Although at first, she despises Mezu for causing his daughters dead, Mamushi becomes completely loyal to him after he helps her to solidify her position as the leader of Yakuza. When confronted by Lo Wang, Mamushi decides to better kill herself, than betray her Oyabun.
Mamushi did have a gentler side and extremely loved her daughter Kazuko. In her diary, she expresses a regret, that her position as the leader of Yakuza, doesn't leave time to spend with her daughter.
Mamushi wears clothes with a snake skin-like pattern. She has an earring in her left ear and has her hair tied.
- Mamushi is also a common name of Gloydius blomhoffii, a venomous pitviper found in Japan.
- Helka also shares her name with Mamushi Type-14 Crossbow.