The main character of the series, like similar boy detectives Shinichi Kudo and Hajime Kindaichi, this 15-16 year old boy is a genius detective. Unlike the other two, however, Touma is not particularly interested in going out and finding wrongs to right. Rather, it is his erstwhile partner Kana who drags him into getting involved. An introvert, he seems to be well-known for his intelligence, but not particularly popular. Sou is introduced when Kana Mizuhara rescues him from an irate customer at a video arcade. He then assists Kana's father in unmasking a murderer. Following that, he and Kana are often seen together, though she denies they are going out. Sou's past is a mystery, and he appears to be a sort of Renaissance man in that he possesses a wide range of knowledge. What is known is that he graduated from the famous MIT in the United States and was planning on continuing his study in a graduate school, but then decided to drop out for unknown reasons and came to join Kana's high school. While highly intelligent, Sou is often seen being amused by such simple things as snowflakes, suggesting he did not have an ordinary childhood. During cases, he becomes even more quiet and it is sometimes hinted that he only solves cases for his own reasons (in addition to Kana's prompting). Sou is also often the unfortunate recipient of Kana's violent tendencies, as he is often bopped on the head for reasons ranging from asking an embarrassing question in public to accidentally looking up her shorts. Despite this, and despite complaining whenever Kana drags him somewhere against his will, he does show concern for her and often takes her along whenever he goes out of town. Besides being a genius, Sou is also quite wealthy and can speak in a number of languages including French. He is seen as having interest in archeology and biology.

(Source: Wikipedia)