Hello World (film) narrative location Japan
Voice cast
Takumi Kitamura as Naomi Katagaki:A 16-year-old high school student living in Kyoto in 2027 and the film's protagonist. Kitamura's experience as a library committee member in his elementary days made him understand his character in the film as a "soft and warm boy" who spends time feeling comfortable with books.
Tōri Matsuzaka as adult Naomi Katagaki / Sensei:Naomi Katagaki's future-self from 10 years later in 2037 and a chief officer in Alltale Management Facility. Matsuzaka was a "little worried" about what kind of animal he would be voicing in this film after dubbing the main character in Paddington (2014) but was relieved to find out it would be a human being instead.
Minami Hamabe as Ruri Ichigyō:Naomi Katagaki's classmate and a fellow book committee member. Hamabe described her character in the film as an "honest and clumsy girl, [with] a strong core". Despite being not used to voice acting, she was given "trial and error" by Itō.Also appearing in the film are Haruka Fukuhara as Misuzu Kadenokōji, the class idol who become friends with Ichigyō; Minako Kotobuki as Yiyi Xu, adult Katagaki's Chinese subordinate; Rie Kugimiya as the crow; and Takehito Koyasu as Tsunehisa Senko, adult Katagaki's colleague and professor at Alltale Management Facility.