Chapter 18

Humans (人間, Ningen) is the 18th chapter of the Parasyte manga series, written and illustrated by Hitoshi Iwaaki.

Overview
''Shinichi's physical and sensing abilities have seen a great increase, which he uses to locate a dying puppy. After the puppy dies, Shinichi places the animal in the trash, greatly upsetting Murano. Migi discusses with Shinichi the change he's underwent, and how he now thinks more like Migi. At school a new transfer student arrives, who just happens to be a parasite that wants to be Shinichi's friend.''

Summary
The parasite formerly known as Ryoko Tamiya is seen visibly pregnant and speaking with another parasite whose body is in the late teens. She requests he observe Shinichi without killing him. The parasite asks why. She tells him that Shinichi is a danger as well as critical data for their future.

On the way to school, dust blows into Shinichi's eye and makes a tear fall. He thinks about how dust can make him cry but his own emotions can't, then focuses on the improvements granted by Migi's integration throughout his body. He hears a faraway conversation involving a Hashimoto, a traffic report from a car, an angrily muttered rant, and Satomi's heartbeat. A truck then drives by and hurts his oversensitive ears.

Despite it, Shinichi had noticed another, nonhuman voice crying out for help, and goes to look. Migi peers up at him consideringly, and points the way when he doesn't find it immediately. In the middle of a road is a small, injured puppy. Shinichi comes up to it, disregarding the traffic around him, and is saddened when Migi tells him the puppy's wounds are too much to save it.

On a park bench, Shinichi cradles the puppy in his arms so it wouldn't die alone in the noise of the street. Satomi comes to sit beside him. She admits that he's changed so much it scared her a bit, and thought his prior, meeker personality was nicer as opposed to his new, colder one. She says she thought she imagined it. Shinichi interrupts by stating the puppy has died and gets ready to go to school, discarding the body in a trash can.

Satomi is shocked but Shinichi doesn't understand her upset, guessing the trash collector would be scared by it. He tells her that now it's dead, it is only meat shaped like a dog. Horrified, she says he's no longer the Shinichi she knew and flees. He sits back, considering that he must have made a mistake, and asks Migi what he did wrong. Migi says the part about a dead dog being only meat sounds like something he himself would say, startling Shinichi.

Shinichi then goes to a child's sandbox carrying the puppy's corpse and scaring away most of the kids. He asks a girl digging if he can borrow her shovel, and proceeds to bury the dog beside a tree. Shinichi then wishes he'd done this earlier so Satomi wouldn't hate him.

At school, Shinichi and Satomi cross paths but she leaves without speaking. He lets her go, knowing she needs more time. Later in class Migi warns Shinichi about a parasite entering the school. He confirms with Migi that it's not Ryoko Tamiya or Uda, and decides to find somewhere to fight. Migi says he doesn't think they'll have to fight, despite parasites of the past attacking them. He then tells Shinichi to be more pacifist, which shocks him into waiting. They decide to meet the intruder where other people are around.

Migi then explains that the parasite felt steadier like Ryoko instead of attempting to immediately approach them, and they might be able to talk. He meets the parasite outside of a senior year classroom, who comments that Shinichi is different from what he's heard. Another student comes up in an attempt to defuse the tension and is dismissively hit and told to stay out of the way. The parasite introduces himself as Hideo Shimada, and announces his intention to make friends with Shinichi and Migi.