He is the president of the student council as well as the president of the puzzle club. Initially, he was a Solver with the title of 'Newton' but was unable to obtain the Phi Brain in his freshman year. The headmaster introduces him to the P.O.G., where he became known as a Giver under the name of 'Minotaur' which was first hinted in the first episode.

Souji is very worried about the well-being of his underclassmen, especially Kaito and his friends, as he vows to himself to guide them to the Puzzle of God. He is well respected within the student body. Even Kaito acknowledges the fact that Souji was able to turn an ugly puzzle into a beautiful one within seconds.

He is mostly seen smiling around others (except the headmaster) and likes to drink boxed apple juice with a straw.