Kanata Saionji is the main male character in the story who is one of the most popular boys in his school, especially to the girls, due to his good looks and cool attitude. Not only does he excel in his studies, but is also good at sports. Shortly after Miyu Kozuki arrives at his home, Kanata's father declared that he wishes to leave on a year long trip to India to try to find enlightenment, thus binding him and Miyu to living together in the same house. His best friend is Santa Kurosu.
Miyu starts attending Kanata's school and they have difficulty keeping their secret about living together, thus started to address each other as cousins. He found out from Miyu's mother that they were both childhood friends and starts to like her more and more. He starts to develop romantic feelings for Miyu as the story progresses (but still teases her to mask it). His mother, Hitomi, was a good friend of Miyu's mother (Miki Kouzuki), and died while he was about 3 years old.
Kanata never wanted to admit his true feelings for others, especially Miyu. He cares for his loved ones very much, such as his family, friends, Wanyaa, Ruu and Miyu. Kanata does have feelings for Miyu as he said in episode "The Weird Object That Seiya Left Behind".
Kanata's favorite food is pumpkin, and likes all its variants, from squash to the chips varieties. In episode "The Blackout Halloween", it is revealed that Kanata had liked pumpkin ever since he was a baby when his mother fed it to him for the first time. Ruu also calls Kanata "papa" because he looks very similar to his real father.
Kanata is shown as an easy-going person and doesn't like to talk very much, unlike Miyu. Even if he seems quiet and a bit cold, Kanata is actually a very loving and caring person to everyone he loves. Even though there are many romantic scenes between him and Miyu, he often makes a joke out of it to cover his real emotions and feelings or by sticking out his tongue to her.
Since he was little, Kanata loved his mother very much, even though he had only known her for a short time. In the manga (Chapter 41), as Miyu and the others went back in time, Kanata went to the time where his mother was still alive. Miyu, who was wearing a yukata (given by Kanata), had the chance to meet Kanata's mother and they both were wearing the same yukata.
In the anime, Miyu goes to boarding school and he is separated from her. He reunites with her and marries her years later. Afterwards, they have a daughter, Miu. They also reunite with Ruu and Wannya.
In the manga, he confessed to Miyu after sending Ruu and Wannya back to their home and kissed her. Years later, he got married to Miyu and still live at the temple, he also had a daughter name Miu who meets with Ruu when she is 12 years old (this story is continued in Shin Daa! Daa! Daa!)
- Kanata's surname Saionji means "west", "park, garden" and "Buddhist temple" (西園寺).