4.312 out of 5 from 100 votes
In secret, alien parasites drift downwards toward Earth. Their directive: to take control of a human body and thrive in secret. When a parasite attempts to take over Shinji, an ordinary high school student, he stops it in his arm to save his mind. With the strange power of amorphous muscle, the curious parasite strikes an uneasy truce with Shinji: it will keep him alive and strong so that it may continue living, and will help protect him from the other parasites that might not take kindly to Shinji's mind still actively working. Can Shinji gain the courage to face the parasites and protect humanity? And would it even make a difference if he did?
In both mangas there are another specie that is infiltrated human society and it is living among them, camouflaged as them, and feeding of the human flesh. Bot of manga have the similar point of wiew at this battle of humans agains the human eating monsters, where they, folowing the main protagonist of the story who is halfling of both species, in deep psychological and philosophical manner question the foundation of our value and moral systems as the "dominate specie" on earth.
In Parasyte, other specie is logical, emotionless, need human body because they are, well, parasyte organisms, they infect humans that where normal before and take over their body destroying that humans individuality.
In Toukyou Kushu, other specie is by nature more similar to humans - have emotions, but they are born different, they have the need to eat human flesh (and human flesh only) which fundamentaly makes them natural enemies of human race.