He is a mathematical genius who is very analytical when it comes to Dueling, using various formulas to create decks to overcome any obstacle. He usually carries six decks as a result and made a seventh made to combat Judaii's deck, though he still lost.
He falls in love with with Tania, the 3rd of the Seven Star Assassins (renamed Shadow Riders for 4Kids). In the third season, he is reunited with her in another dimension and stays behind to be with her.
In the second season he willfully joins the Society of Light after Takuma Saio (Sartorius in the 4Kids dub) uses Daichi's own self-doubt and desire to be accepted against him. Although Daichi joins, he is not given any position of power and neglected to the sidelines. Eventually after talking to a physicist named Dr. Albery Zweinstein (Dr. Eisenstein in the 4Kids dub) Daichi's confidence soars and he leaves the Society, stripping himself naked in the process, which showed off his muscular body in the process.
In the manga, Daichi has romantic feelings for Asuka Tenjoin (Alexis Rhodes in the 4Kids dub) and has a much bigger role than in the anime.