a withered version of the tree that she and Mashiro sat under together, and later in volume eight, a knight after overcoming her difficulties. In that same volume, she obtains the key to graduate, but chooses to not graduate. After she wakes the nurse asks her reason why, to which her response is she wishes to see Mashiro graduate, even if that means she may have lost her own chance. Coming off as an aloof womanizer, first seen dispassionately with a girl having sex with him, Sou merely has a blunt personality and genuinely tries to fall in love, albeit doing so through sex. Ever since he found out that Mashiro Ichijo was part woman, he has been trying anything to get Ichijo to love him, even going so far as to admit his love to him in the second volume. Sou has an older sister named Ai, whom he has very serious issues with. Ai and Sou's parents had separated when they were children, Ai going to live with their father and Sou with their mother. His mother spending more time on her career, Sou went to visit his sister. When he saw Ai playing with her step-mother and puppy and not the teddy bear that would be her "Sou", he ran away. Feeling betrayed that his sister seemingly moved on, he ended up catching pneumonia after collapsing in the rain. The series of events was so traumatic that he ended up seeing and hearing hallucinations. The illusions can affect him so strongly that he can see an entire room differently from someone else. Dream Self: Sou's sister, Ai, tells Mashiro that Sou is the Black Knight that torments Mashiro, and later, Sou tells Mashiro that he was hiding behind the knight's armour. Volume nine sees Sou resolve his sister issues, and shows that up to that point Sou's dream self was partly the dream Ai, and partly her teddy bear, which supposedly represented "him" to her. After this, Sou's dream form becomes a dog friendly to Mashiro. Sou's older sister, first seen in the dream world. She is dark with a slightly sadistic sense of humor. Ai also claims in volume two to know what happens after a student graduates. Ai actually attends a different school several blocks away, and only sneaked into the dream class to keep Sou from graduating. She has a strong brother complex, claiming