Shintarō Natsume

A soft-spoken, third-year student and an underling of Hajime Kanzaki, he shows exceptional interest in Tatsumi Oga and his exploits. Handsome and long-haired, he prefers to make light-hearted quips during frays to engaging in them personally. Though he rarely participates in fights himself, he is incredibly strong, taking out the MK5 by himself and even downing Kaoru Jinno, an underling of Hidetora Tōjō's within seconds. From this it is implied that Natsume is significantly stronger than previously credited, as not even Kanzaki or Tatsuya Himekawa were capable of such a feat. He shows these fighting skills again when he blocks Hiromichi Gō from attacking Oga head on, later stating during their fight, "It's not really my style to go all out in a fight."

Appearance
Natsume is shown to be a tall, mildly muscular individual with neck-length brown hair and matching eyes. Natsume has also been shown as being handsome. He commonly wears a hoodie when not in school uniform.

Personality
Natsume is an extremely laid-back and mysterious character. He normally displays mild amusement to most situations, even dangerous ones other characters are serious about. He likes to keep tabs on people he finds "interesting" such as Kanzaki at first and then later Tatsumi Oga. He seems to have some sort of hidden agenda as while he is technically an underling of Kanzaki, he has displayed strength that far surpasses the other delinquents, having been able to single-handedly defeat the MK5 and fight on equal terms with a member of the Rokkisei. In an extra episode of the anime, Himekawa stated that Natsume had no need to follow Kanzaki, and Natsume answered by saying that he only did it because it was fun since Kanzaki was so active.

Tōhōshinki Arc
He first appeares when Hajime Kanzaki and witnesses his defeat by Oga. After that, he takes a keen interest in Oga's affairs. Oga and Natsume meet again in a supermarket where Natsume works part-time and he tells Oga that he just defeated one of the Tōhōshinki and that there are three more Oga must contend with if he is to become the strongest delinquent in Ishiyama High. Natsume then appears in the middle of Oga's ongoing confrontation with Aoi, witnessing Nene and Chiaki confront Oga about Aoi. He defeats the MK5 all by himself when he learns they ganged up on Nene and Chiaki, dealing with them while Nene warns Aoi that they were set up by Miwa to fight Oga. During Oga's battle with Tojo, he saves Kanzaki and Himekawa from Aizawa and Jinno's attacks, and also ends up helping them out of the Ishiyama building explosion caused by Oga. Out of all the students who were involved in the explosion, Natsume was the only one to escape uninjured.

Saint Ishiyama Academy Arc
Natsume defends Oga from an attack by Hiromichi of the Rokkisei. They had a reasonably matched fight, but only because Natsume pointedly claims he held back. He is one of the seven Ishiyama students who played in the volleyball match against St. Ishiyama to avoid expulsion.

Prince En Arc
Natsume is part of the team that plays video games at Himekawa's apartments to help locate En. He also went to the store to get food for everyone along with Lamia and Furuichi where they encounter Yolda and find out they've been playing next door to them all along.

Akumano Academy Arc
Natsume, along with the other Ishiyama students, train under Zenjūrō Saotome for the upcoming fight with Akumano Academy. He is shown to be fighting against Kanzaki to a standstill during the training. Later, Kanzaki's gang with Izabella arrive at Akumano Academy to complete one of Quetzalcoatl's games required for Oga to continue. However, the game is interrupted with the arrival of Lindworm.

Abilities
Natsume is shown to be stronger than most of the other delinquents. It is assumed he could even crush Kanzaki and Himekawa if he wanted to and is also capable of fighting on par with Hiromichi Gō of the Rokkisei who is a mixed martial arts junior champion. However, the true extent of his abilities is unknown since he is rarely seen fighting, and when he does fight, it is never at full strength. He is mostly seen using kicks as his main fighting technique.

Quotes

 * "It's not really my style to go all out in a fight" - When fighting Gō.
 * "Ah, but Kanzaki-Kun is a tsundere." - Commenting on Kanzaki's personality.

Trivia

 * Natsume has light-brown hair and eyes in the manga, while they are portrayed as purple and black respectively in the anime.