Nobuko Izumi (Parasite)

The unnamed parasite who kills and takes over the body of Nobuko Izumi (Shinichi Izumi's mother) and impersonates her. Due to a car accident, her original host body is fatally damaged and she swaps host twice to try to survive. She stabs Shinichi in the heart while looking for Nobuko's husband and witness to her death, Kazuyuki Izumi, and is killed later on by a tag team of Shinichi and Mamoru Uda.

Appearance
Her initial appearance is that of a woman with brown hair.

Her second appearance of the man she had been riding with, male with black hair.

Her final appearance is of Nobuko Izumi, a fair-skinned woman with short brown hair, brown eyes, and a distinctive burn scar on her arm. Notably in the anime, due to her attack which cut part of Nobuko's hair in the process, her mimicry of Nobuko also has the uneven trim.

Personality
She appears determined to kill any witnesses, traveling from one city to another and back simply to find Kazuyuki Izumi so she can eliminate him. However, she is also predictable and straightforward, attacking both Shinichi Izumi and Mamoru Uda by aiming only for their hearts and assuming that they would be dead after one strike without waiting to see them die or finishing them off.

She has some poor understanding of basic human information; she assumed that male and female bodies were similar, and had no familiarity with seat belts. Otherwise, she is a fairly generic parasite.

Plot


The parasite is first seen in a car with another man who had picked her up in hopes of a one-night stand, though she plans to eat him. She displays unfamiliarity with the function and usage of a seat belt, which distracts the man and causes him to drive off a mountainside road. Her host body is badly damaged, but because the man had been wearing his seat belt he was mostly unhurt, and she decides to decapitate him and switch bodies.

However, she is unable to control his body's reproductive organs and wets herself, which in the manga gets her kicked out of a truck. She walks further along the road until her male host body starts rejecting her, and she goes to find a female host to transfer to, assuming it would accept her.

At a cliffside, Nobuko and Kazuyuki discuss the vacation as well as how Shinichi might be doing without them. The parasite comes up behind Nobuko and Kazuyuki attempts to warn her to no avail as she is swiftly decapitated. He falls over a cliff out of the parasite's reach which prompts her to hunt him down.

She visits the hotel they stayed at, pretending to be Nobuko, then heads to their home and finds Shinichi. She stabs him while he is conflicted with Migi about defending himself from her.

Later, after she had made her way back to the original city she came from, she detects Uda and Jaw (still named Parasite), and follows them to a cliff. She is surprised at having found two "failures" and attacks him. Jaw defends him, but due to his position Uda is unable to breathe through his mouth, which leaves him and Jaw at a disadvantage from lack of oxygen. Shinichi arrives in time to see the parasite stab Uda in the chest, and Uda topples over the cliff.

Despite Migi's dormancy, Shinichi manages to overpower the parasite due to his rage and his new superhuman abilities and prepares to kill her. She brings up her hand in defense, showing Nobuko's burn scar and causing Shinichi to bring down his guard enough for her to recover. She prepares to kill him, but Jaw sneak attacks her from behind and successfully decapitates her, explaining that because she had been conspicuously aiming at Uda's heart Jaw was able to shift his internal organs out of the way before she stabbed him. Uda tells Shinichi that no child should have to kill their own mother.

Impact
It cannot be overstated the impact this parasite has on Shinichi in two sudden acts. By killing his mother, she gives additional motivation to one of the men most in a position to do direct damage to her kind. His grief and trauma and how he deals with them at any given moment shapes the Shinichi's life from then on.

It colors all of his interactions with Hideo Shimada, causing Shinichi to be more suspicious and aggressive. It causes him to become more proactive in fighting parasites in order to protect his loved ones. It colors his reunions with Ryoko, filling him with disgust and rage at her apathy towards her own child until she too sacrifices herself.

By fatally stabbing him, she forces Migi to act creatively in a way that ends up making him stronger to the point he can go toe to toe with most parasites without any active assistance from Migi.

Shinichi furthermore develops the ability to calm very quickly from extremely high levels of stress, though he temporarily loses the capacity to cry from grief.

Abilities & Powers
Being a parasite, she can shapeshift from the head up and and harden her cells for offensive or defensive purposes,as well as detect other parasite signals and automatically emit her own. She can also maximize the host body's physical potential and disregard pain.

In the anime, she is the only parasite seen to imitate an inorganic object (Nobuko's hair clip).

The scar on her host's hand causes Shinichi to hesitate to kill her.

Weaknesses
Like all parasites, she requires a host body with functioning organs to survive, and would die if she were separated from the body or it was destroyed. Fire can cause her parasite cells to "freak out", making her lose control. She is also susceptible to poisons or caustic chemicals, which would either kill parasite cells on contact or make her host body fail.

Her lack of imagination and predictability made it possible for Jaw to prevent her from fatally wounding Uda and sneak attack her in turn.

Trivia

 * In the movie Parasyte: Part 1, the parasite that takes over Nobuko Izumi's body is A.