Maesawa

Maesawa was a parasite who, along with Kusano and Hikawa, suspected that Reiko Tamura was a traitor and tried to kill her.

Appearance
Maesawa's host body was a middle-aged man with short grey hair and black eyes. In the manga, he appeared to be much younger.

Personality
Maesawa was very confident; he claimed that he can beat Reiko Tamura with his own strength. Just like Kusano and Hikawa, he suspected that Tamura Reiko was dangerous to them.

In the anime, he expresses disdain towards the parasite that killed Kana due to it choosing to feed where and when it wanted, instead of using their planned locations for safety.

Plot
In the anime, he is introduced much earlier, albeit with very minor and small scenes.

Late at night, he along with Kusano and Hikawa cornered Reiko and prepared to kill her. She runs away and he begins to chase her until she stops in a construction yard. He then states that he could beat her one on one, due to his body's muscles being stronger. As Reiko attacks him, he quickly catches her tentacle and cuts it off while mocking her, when suddenly the detached piece pierces his back and enters his body. He begins writhing in pain as Hikawa arrives on the scene and watches as his body is destroyed from the inside out. He then jumps on top of Hikawa, pinning her down, claiming he has no control over his body. Finally, the piece of Reiko bursts out of his stomach, killing him.

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

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

His confidence allowed Reiko to easily get a portion of herself behind his defenses and kill him, as he assumed she was finished when he cut off her tentacle.