Reference of Rio’s Grandmother: Professor Zero.
Professor Zero was a proud , smart, and wealthy Mathematics professor. She is the grandmother of Rio and Mother to Rio’s father. She is very known for her pride, cockiness, and rudeness towards those with less intelligence. At rare times she would show a caring and nurturing deposition even when she still feels the urge to point out mistakes in an mockingly embarrassing way.In case you’d like to know: Rio gets most of her looks, and some of her knowledge from Zero.