Masane Amaha, whose real name is Yasuka Ohara, is the main protagonist of the anime. Her background is defined by a catastrophic event known as the Great Quake, which devastated Tokyo six years before the story begins. During that disaster, she was found at ground zero, uninjured but holding a baby girl, and she had lost all memory of her life before that moment. She came to believe the child, Rihoko, was her own daughter, and the two formed an inseparable bond. In the years following, they lived on the margins of society, frequently on the run from the NSWF, a government child welfare agency that deemed Masane unfit to raise Rihoko.

Masane is a kind-hearted and well-intentioned woman, but she is also clumsy, flighty, and absent-minded. She often appears scatterbrained and ditzy, to the point where Rihoko sometimes seems more mature and takes care of household matters. Despite this, she is fiercely devoted to her daughter and is willing to make any sacrifice to ensure Rihoko’s safety and happiness. Her primary motivation is to provide a peaceful, stable life for Rihoko, free from the constant threat of separation. This maternal instinct drives her to accept dangerous responsibilities and face overwhelming odds.

Her role in the story begins when she is arrested and separated from Rihoko, triggering the awakening of the Witchblade. This ancient, mystical weapon has been passed down through generations of women and chose Masane as its bearer during the Great Quake. After her transformation, she is conscripted by the Doji Group, a powerful corporation, to destroy X-Cons—rogue, murderous beings created by the company. In exchange, Doji provides her with the resources to live independently and raise Rihoko without NSWF interference. Later, she also confronts Cloneblades, artificial replicas of the Witchblade wielded by the NSWF’s Neogenes.

Key relationships include her adoptive daughter Rihoko, who is the emotional center of Masane’s life and her moral compass. She develops a complex connection with Takayama, a Doji executive who offers her employment and support, as well as with Reina, a former lover of Takayama who becomes both ally and rival. Journalist Tozawa investigates her story and becomes a trusted confidant. Throughout these interactions, Masane’s unwavering priority remains protecting Rihoko, even when faced with painful revelations about their true parentage—Rihoko is not her biological daughter, but Masane’s love for her never wavers.

Over the course of the series, Masane undergoes significant development. She begins as a struggling, amnesiac single mother barely getting by, but she grows into a formidable warrior capable of wielding the Witchblade’s immense power. She learns to control and trust the weapon, evolving from a reluctant fighter into a determined protector. A pivotal moment occurs when she confronts the true nature of her connection to the Witchblade, forcing her to make harrowing choices that test her will to protect Rihoko at any cost. Her journey is one of self-discovery, resilience, and the relentless pursuit of a better future for her child.

The Witchblade grants Masane extraordinary abilities: enhanced strength, speed, agility, and rapid healing. It can manifest as a blade from her arm, extend her hair into cutting weapons, and adapt its form to suit her needs in battle. However, the power comes with a heavy price—it consumes her both emotionally and physically, and its influence can drive her to a battle-hungry state. Throughout the story, Masane’s control over the weapon improves, allowing her to access more powerful forms as the stakes of her conflicts escalate. Despite the burden, she remains defined not by her supernatural abilities, but by her unyielding love for her daughter and her determination to overcome any obstacle.