Editor-in-Chief of Weekly Jump. He tends to behave indifferently or even coldly but it's all for Jump's authors and editors to regain their spirits. He has a good eye for manga and believes it's most important for a manga to be interesting. He's not afraid to make a gamble in order to make the magazine better, but will not put authors' lives at risk.   He knew Saikou's uncle, Kawaguchi Taro, since he was the Assistant Editor-in-Chief at the time Kawaguchi Taro had to quit. 

Moritaka Mashiro and Akito Takagi are pretty much foils of each other. Mashiro, an average 9th grade student but talented artist, and Takagi, an overall advanced 9th grader and aspiring writer. After great convincing, Takagi convinces Mashiro to join him in becoming the greatest mangakas Japan has ever seen. Takagi, with his gift of writing, hopes to become a successful mangaka, and Mashiro, with his gift of art, hopes to marry the girl of his dreams, Azuki Miho. 
(Source: Anime News Network)

Average student Moritaka Mashiro enjoys drawing for fun. When his classmate and aspiring writer Akito Takagi discovers his talent, he begs Moritaka to team up with him as a manga-creating duo. But what exactly does it take to make it in the manga-publishing world?
 
(Source: Viz Media)

Moritaka Mashiro and Akito Takagi have come a long way since they started making manga in middle school, but trials still await them as they head towards their goal of getting an anime adaptation for one of their manga. As they continue to grow as artists and as people, they will be faced with new friends, new rivals, and new hurdles to overcome. 
(Source: Anime News Network)

After the decision to serialize Moritaka and Akito has been made, they are introduced to Miura, their new manager. At first, the two thought it was a joke, but Hattori gives them a pep talk before leaving. While Miura doesn't seem like a bad person, he is given to rudeness and seems to be worried about the duo's future. In addition, the duo are given three assistants to work on their manuscript, and with the assistance of Ogawa, an experienced assistant, their work progresses well. 
At the start of the new year, Moritaka and Akito both attend Shonen Jack's New Year Party. There, they meet Hiramaru Kazuya, said to be a genius of a whole different level from Eiji.