Character Arc
Jeong Su-in is the protagonist of Parasyte: The Grey, a reserved young woman working an ordinary job whose life is upended when an alien parasite attempts to take over her body during a violent emergency. Because she was gravely injured at the moment of infection, the parasite is forced to divert its energy to keep her alive and cannot fully seize control, leaving the two of them sharing a single body in an uneasy, alternating arrangement.
Her arc centers on this forced partnership and the question of identity it raises. Su-in must learn when to cede control to the creature, nicknamed for the way it surfaces, and when to assert herself, all while carrying the weight of a lonely past and a wary relationship with the people around her. As Team Grey closes in and parasites infiltrate the community, she is pushed from passive survivor toward someone who must decide what she is willing to fight for.
Across the six episodes, Su-in's story becomes the show's emotional anchor: a study of coexistence, trust, and self-worth told through the literal experience of sharing her mind with another being. Jeon So-nee's performance shifts between vulnerability and steely resolve, and the character is positioned to continue into the announced second season.