Rio is seen to be bothered by Yuma occasionally, such as when he calls her "Shark's sister" (in the dub, he calls her by her first name). Still she seems to be relatively kind and friendly to him and is grateful for his actions with Shark, returning him to his original disposition. (in the dub, Rio likes Yuma for his sense of humor) Also Rio seems to care for Yuma in a way, as she was distraught, just like her brother, at knowing she would break her friendship with Yuma after learning about their Barian past. After Rio accepted her fate as a Barian, like her brother, she was also emotionally distraught at the thought of becoming Yuma's enemy and distraught of breaking her friendship with him.