|Anime debut||Episode 13|
|Manga debut||Chapter 44|
|English Voice||Rutherford Cravens|
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.
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.
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
As a parasite, Maesawa has the basic abilities to shapeshift his head, and maximize the physical potential of the body he's controlling. He can harden his cells for offensive and defensive purposes.