Chapter 22

Fissure (亀裂, Kiretsu) is the 22nd chapter of the Parasyte manga series, written and illustrated by Hitoshi Iwaaki.

Overview
''While out with Satomi, Shinichi becomes aggravated and yells at her after he's continuously asked why he's changed. Yuko is told by her brother about the existence of the parasites in order to keep her safe. However, after following Hideo, she learns that he's one of these creatures. At school, she tries to talk him out of killing more people, which causes Hideo to prepare to kill her instead.''

Summary
The manga flashes back to Shinichi's final year of junior high, where he has just passed the exam to head to West High. On the way out he passes by Satomi Murano, who reminds him they took the test together, then introduces herself and tells him she hopes they'll be in the same class.

In the present, Shinichi asks Satomi if something's wrong, as she's unusually quiet. He tries to make conversation about Kana, then realizes his mistake. As they cross paths with Hideo, he asks what Shinichi did to Mitsuo's gang yesterday and if he "used his hand" to beat them up. Shinichi tells him no, then demands he leaves. Hideo does so.

Satomi then cries out as Shinichi had gripped her arm tightly enough to leave marks and he hurriedly lets go.

In a diner together, they discuss Hideo, with Shinichi angrily insulting him which unsettles Satomi because it's uncharacteristic of him. He tries to play it off as an attempt to be more wild, and Satomi tells him he shouldn't force himself to change. He asks her if being stronger isn't good. She states that it's better to be weak than a thug. Shinichi doesn't understand.

Satomi then tells him that she feels like he's forcing himself to be something he's not, and he denies it, saying that he's not forcing it. She asks how she can change this much, and when she pushes the subject, about to ask if he's Shinichi again, he yells at her to shut up. She then leaves, saying she thought he was someone else.

At home in the evening, Migi tells him that he's become psychologically stronger as a living creature, rather than as a human. He is less easily rattled and recovers from emotional pain faster. Migi then tells him that it's good to avoid showing Hideo weakness, so this strength is to his advantage, and that Satomi is a weakness that Hideo could have taken advantage of if he knew more about human romance so it's better for her to stay away.

Shinichi asks if Migi was trying to cheer him up. Migi tells him that if he has no appetite it affects Migi too, so will try to cheer him up if needed.

Yuko tells her brother in the morning that she's skipping school today due to a headache, and once alone thinks again about Hideo's injury by a baseball. She calls the school and pretends to have been sent one of Hideo's letters to gain his house address. At his apartment, she hides away in time to see him return home, then leave again while differently dressed. She follows him downtown and witnesses him change his face completely. On the way home, she thinks about her brother's recent case and how this is what he's up against. She considers telling him, but decides not to because she hasn't heard of anything happening to their class.

Hideo fails to attract any humans and muses that human tastes are too complicated for him to follow.

At home, Yuko bugs her brother about the parasite case until he gives in. He explains that they don't know what this new phenomenon is, only that they can pretend to be human and they eat people. He warns her not to walk alone in the dark, but there's few compared to humans so she's unlikely to see one anyway. He then thinks out loud, wishing they could catch one alive. Yuko immediately answers no to him asking if she knows one.

Yuko wonders in bed if they really eat people, and realizes Hideo must be a murderer. She first plans to tell her brother, then uneasily recalls him hoping to catch one alive and instead decides to talk down Hideo. She contemplates how to defend herself, understanding that she won't be able to cut or hit him due to the parasite ability to change shape and harden cells. She then considers chemicals and visits the science room.

Later she talks alone with Hideo, revealing that she saw him changing shape, that there are people aware of parasites and that if he is killing people he needs to leave and stop killing. Hideo asks how many know.

Migi accidentally snaps Shinichi's pen in class.

Yuko states that if he were a human she'd call a police, but she doesn't know what to do because he isn't. She turns back to see Hideo beginning to morph, him stating that this is very bad, and realizes she should have just told her brother. He spirals apart into a bladed tentacle.

Shinichi stands up, calling Hideo an idiot for acting in broad daylight and bewildering his teacher.