Niki Jumpei is a fictional character from the Japanese manga and anime series titled Kiseijuu: Sei no Kakuritsu, also known as Parasyte. He is a high school student who becomes partially infected by a parasitic alien that takes over his right hand. This unique situation leads him to navigate a world where humans and parasites coexist, often in conflict. As the story unfolds, Niki struggles with his identity and the moral dilemmas posed by the presence of the parasites. He forms alliances with other characters, including Migi, the sentient parasite in his hand, and confronts various threats to humanity.