Thomas H. Norstein is the central protagonist in Digimon Data Squad. He is a genius. His partner Digimon is Gaomon.
He is voiced by Hirofumi Nojima in the Japanese version of the anime, and by Crispin Freeman in the English version of the anime.
Thomas is a tall teenager with pale skin, straight light blond hair, and light blue eyes. Thomas's civilian attire consists of a dark green v-neck T-shirt, white pants and brown shoes with black soles.
After his memory erased, he begins wearing a white short-sleeved button-up shirt under a green unbuttoned vest, as well as a blue tie, dark blue trousers and brown dress shoes with black soles.
Thomas is a gentlemanly and boy genius who graduated from the Stockholm Royal University of Science at the age of 13. His abilities are considered elite, even within DATS. He bases his operations on data and theoretical principles, and as such, his personality clashes with Marcus's. Calm and shrewd, he is the exact opposite of Marcus and sees him as a rival. He has an elitist attitude but he gets emotional when thinking of his mother. Thomas's loyal partner is Gaomon, who always addresses him as "sir" and is easily angered when he thinks someone is disrespecting Thomas.
Before meeting Gaomon
His mother was overall Japanese, and his father is a prominent Austrian aristocrat named Franz Norstein.
Franz met his future wife while she was an exchange student in Austria, and Thomas lived with his mother in Japan.
He and his mother would always go to the park and would always get ice cream.
However, when a festival came to town, his mother was killed being run over by a truck as she pushed Thomas out the way so he wouldn't get hurt. Thomas was shocked after seeing this since the only thing that was left of his mother was one of her sandals. After this he was taken back to Austria. He also has a half-sister named Relena who suffers from a strange disease.
It is never shown who Relena's mother is, but she died of complications during childbirth. While Thomas does not particularly care for his cold-hearted father (at least not until after the events of episode 42), he does love his sister very much and does whatever he can to protect her. Years later he met Gaomon. As he got older, he is shown living by himself while having a butler. Thomas is a 14-year-old boy genius who graduated from the Stockholm Royal University of Science at the age of 13. His abilities are considered elite, even within DATS. He bases his operations on data and theoretical principles, and as such his personality clashes with Marcus's.
- Thomas H. Norstein is the same age as Marcus Damon.
- Marcus's nickname for Thomas is "Thomas H. Nerdstein".
- When he was a child, he is voiced by Mona Marshall is the best-known voicing as Izzy Izumi from Digimon Adventure/02/tri. and Terriermon from Digimon Tamers.
- His English Voice Actor, Crispin Freeman is best known voicing as Tsume from Wolf's Rain, Itachi Uchiha from Naruto/Naruto Shippuden, Shizuo Heiwajima from Durarara!! and Koichi Kimura from Digimon Frontier.
- He and Matt Ishida have different Digimon Partner look like Dog and Wolf's Digivoluition:
- Gaomon is a dog and Gabumon is a wolf.
- He is the half brother of Relena Norstein.
- Like Matt, his Data Link Digivice is blue.
- His Japanese Voice Actor, Hirofumi Nojima, who also voiced Joshua in Fire Emblem: The Sacred Stones, Who's-Who in One Piece, Warz Gill in Kaizoku Sentai Gokaiger, Sandman in JoJo's Bizarre Adventure: Steel Ball Run, Clown in Soul Eater, Reiji Namikawa in Death Note, and Phantom in Happiness Charge Pretty Cure!.