Maesawa

Maesawa is distrustful of behavior that threatens the collective security of the Parasites. He supports Kusano's suspicion that Reiko has become unpredictable and potentially dangerous to their group.

He is willing to cooperate with other Parasites rather than living entirely as a solitary predator, but that cooperation depends on shared interests rather than emotional loyalty.

Canon gives him less individual characterization than Kusano, with his most important actions occurring as part of the faction opposing Reiko.

Maesawa is a mature head-infecting Parasite with the standard capabilities of his species.

He can transform Parasite tissue into hardened blades and other weapons, control his human host body and detect the signals emitted by nearby Parasites.

Maesawa is dangerous in coordinated combat, particularly when attacking alongside other Parasites, but he does not demonstrate the exceptional cellular control possessed by Ryouko Tamiya.

Maesawa operates within the organized Parasite community associated with Takeshi Hirokawa.

He sides with Kusano as suspicion grows around Ryouko's experiments, her interest in humans and her unwillingness to support straightforward measures against perceived threats.

Maesawa, Kusano and Hikawa eventually attempt to kill Ryouko together. Despite facing three Parasites, Ryouko uses separated portions of her own tissue to fight them simultaneously and defeats the group.

Kusano is Maesawa's principal ally and the leader of the faction that moves against Ryouko.

Hikawa joins Maesawa and Kusano in their opposition to Ryouko.

Ryouko Tamiya becomes their enemy as her priorities diverge from those of the organized Parasites. Maesawa participates in the failed attempt to assassinate her.

Takeshi Hirokawa leads the broader organization within which Maesawa operates.