Shiori is Kurama's (aka Shuichi) mother, and is in the hospital when she is first seen in the anime. She does not know that her son is a demon. Later on, Shiori marries a man who, ironically, has a son with the same name as Kurama's human name, Shuuichi. For the English dub, they changed his name to Kokoda, most likely to prevent confusion.
Shiori is by far the most important person in Kurama's life. He would do just about anything for her. He would even go so far as to wish for the restoration of her life, from the Forlorn Hope mirror, at the cost of his own.
Ever since Kurama came into her life 15 years from the day he was mortally wounded by demon bounty hunters, she has been his role model and inspiration, the very foundation of his humanity. No matter what case he is helping Yusuke solve or any tournament he may be in, Shiori is always on his mind and in his heart.