Touko Hizuki

Ayana's older sister. A scientist who often acts on her whims and loves to experiment with drugs of her own making, the effects of which often backfire on her and the rest of the cast in humorous ways. Due to her infatuation with the Invisible Man, she somehow gained the ability to make herself invisible at will. At some point, she started working as the school nurse. When she was younger, she's drawn an embarrassing romance manga featuring herself as the protagonist, as well as used her drugs to make two of her muscular male teachers fall in love with each other.