|Anime debut||Episode 11|
|Manga debut||Chapter 27|
|English Voice||Kalob Martinez|
Kusano (草野, lit. Kusano) was one of the parasites responsible for the deaths of Kuramori's wife and their daughter. He suspected that Reiko Tamura was a traitor and, along with Maesawa and Hikawa, tried to kill her.
He had short black hair, with an average height and build. He was seen wearing gray dress pants along with a black pinstriped vest and a gray long-sleeved shirt.
He is reactionary and aggressive against perceived threats, advocating for Shinichi to be killed and trusting his instinct that Reiko was no longer an ally due to her decisions. He is disloyal even for a parasite, willing to kill parasite allies if it meant getting rid of Reiko and keeping his plans secret from the higher-up members of their group. It's noted that he later begins showing impressive signs of expressing anger.
He appears to help lead the parasite group, managing a laptop in a meeting in the anime and holding onto files involving Shinichi in the manga.
Kusano is first seen driving Gotou around the corner from a building where the Yakuza were holding a meeting. He comments on Gotou's appearance when he returns and drives off. They return to their headquarters and inform Hirokawa of their success. As they leave, he reminds Gotou of Reiko's maternity leave.
He is later seen during Hirokawa's campaign speech, standing on top of the stage with Hirokawa, Gotou and three other people.
He partakes in several meetings between the other parasites and Hirokawa, often advocating for Shinichi Izumi's death and expressing distrust for Reiko's plans when they could potentially expose the parasites.
Following the death of a parasite that's killed by Shinichi, he begins to suspect Reiko Tamura who seems to be defending Shinichi despite his danger towards them. When their group assigned someone to annihilate Shiro Kuramori, but failed as they only managed to kill his family, Tamura warns them to not underestimate the human race; however, due to this statement his doubts toward Tamura increased. Later that night, working with Maesawa and Hikawa, he finally decides to kill her.
Kusano along with Hikawa and Maesawa emit strong signals of animosity, luring Reiko to their position. After trading words, with Reiko comparing him to Mr. A and commending them for deciding to kill her, and Kusano informing her that Gotou and Hirokawa know nothing of their plans, Reiko makes her escape. While chasing her down, he decides that it's okay for people to see them as long as they kill her. Sensing that Reiko split herself in two, Kusano follows the section containing her human portion into the city. After witnessing Reiko's recklessness of leaving her body and her apparently irrational behavior towards a human couple, and sensing the death of one of his allies, he leaves.
At the construction site, he begins attacking Hikawa, who is having her body destroyed from the inside. He claims that he can't be sure who's in control, due to her trying to get close to him. As Hikawa begs for her life, he mocks her while dismembering her body and drawing her animosity. After killing her, his body is slashed into three pieces by the body attached portion of Reiko, who had snuck up while he was focused on her detached portion. Trying one last time to kill her, he is easily knocked away and begins to die. Reiko leaves him with a quick explanation of her deceptive strategy and he shrivels up and dies.
Abilities & Powers
As a parasite, Kusano 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.
Kusano is one of the few parasites shown to transform his parasite body into a mobile form after he was detached from his host.
- The name Kusano means "grass, weeds" (草) (kusa) and "plains, field" (野) (no).