Chapter 15

The Missing 30% (消えた30%, Kieta 30%) is the 15th chapter of the Parasyte manga series, written and illustrated by Hitoshi Iwaaki.

Overview
''Shinichi talks with Uda and they quickly become friends, and decide to work together and kill the parasite that killed his mom. Migi later informs Shinichi that after saving his life, he lost 30% of his original body in his bloodstream, resulting in the sudden increase in his physical abilities. Uda is able to track down Shinichi's mother and lure her to the bay, where he and Jaw (then called Parasite) begin fighting her.''

Summary
Uda begins his backstory, explaining that his wife divorced him and a parasite found him as he was standing over a cliff. When it attacked he fell off the cliff and into the ocean, where he was knocked unconscious. The parasite takes over speaking, explaining that as he entered he realized that Uda was drowning, which would lead to them both perishing, so quickly took over the chest and mouth and stretched out past the water to breathe for Uda.

In the present, Uda states that he'd been afraid when his parasite warned him of another one approaching, expecting a monster. He then asks Shinichi to tell him about their story, and Shinichi requests they move back to the hospital.

Down by the seawall, Makiko walks around looking for Shinichi.

Shinichi explains about his father and the parasite hunting them to Uda on top of the hospital's roof. Uda begins crying, and both his parasite and Migi express their confusion about humans. Uda comments on Migi's polite speech, which Shinichi assumes was learned from books, and the parasite which Uda introduces as Parasite states he learned from the movies Uda rents and cries over.

Uda then requests that Shinichi call him if the parasite they're waiting for appears, wishing to help someone else like him.

At night, Migi tells Shinichi that earlier today he had been running like an Olympic athlete and jumped over a high wall. Migi then splits up into smaller and smaller pieces, revealing that as his pieces shrink they lose the capability of thought and can only follow simple directives. He then reveals that tiny parts of him washed away in Shinichi's body after he'd repaired the heart, and only 70% of him made it to the hand. Migi states that he'd had to gather cells from the rest of the body to make up the rest of Shinichi's arm, from slightly above the elbow to the shoulder where Migi had originally taken up space.

Shinichi asks if some might have got into the brain, thinking about his earlier inability to cry despite his grief. Migi expresses uncertainty, but thinks they wouldn't have been able to get into the capillaries.

A few days later, Shinichi asks Makiko if he looks human, and is relieved when she says he does. Annoyed at his crypticness, she asks what's wrong and why he looks so sad at times, then leaves.

When Shinichi re-enters the Namiki Inn, Makiko's mother tells him he has a call from Uda, who says a parasite is approaching him. Shinichi realizes that Uda has never met another parasite before and warns him that the parasite will attempt to kill him as soon as it realizes Uda's brain is still human. Both Uda and Shinichi agree to head to a cape between their towns, and Uda then flees from the parasite wearing Nobuko's face.

On the way, Migi detects Parasite's presence, but falls asleep before he can detect the other one. Shinichi refuses to turn back and get Uda killed, so Migi morphs into a sword for Shinichi's arm before he falls asleep.

Uda is struggling to continue, already winded from his lack of endurance despite Parasite urging him on. Parasite states that parasites can push their human host bodies to the limit and tells Uda to run, which he protests because Shinichi is coming. Parasite then tells him to take a side road so the parasite will be trapped between him and Shinichi.

Nearby, Shinichi is wondering where they are because Migi is unable to direct him.

Uda finally stops on a short cliff overlooking the ocean. The parasite with Nobuko's body comes up behind him, stating it strange that she met two failures in a row, and deciding to kill him. Her face then splits, horrifying Uda and intriguing Parasite. They begin to battle, Uda quickly disadvantaged because Parasite's form prevents him from breathing through his mouth.

Shinichi hears the sound of blades and realizes he overshot.