- Celebrity Voice Actor: In the original Japanese version, Kyuta is voiced by Aoi Miyazaki as a child and Shōta Sometani as an adult, Kumatetsu is voiced by jidaigeki and film actor Kōji Yakusho and Kaede is voiced by model and actress Suzu Hirose.
- Children Voicing Children: In the Latin American Spanish dub, Iván Bastidas and José Luis Piedra, who voice Ren/Kyuta and Ichirohiko's younger selves, were children at the time of recording.
- Cross-Dressing Voices: Averted in the Latin American Spanish dub with Ren/Kyuta and Ichirohiko's younger selves, where they're voiced by actual young boys.
- Dawson Casting: In the Latin American Spanish dub, the nine-year-old Ren/Kyuta was voiced by 15-year-old Iván Bastidas and the younger Ichirohiko was voiced by 13-year-old José Luis Piedra.
- In Memoriam: The Latin American Spanish dub of the film is dedicated to the memory of Maria Dolores Uribe, Takamasa Sakurai, Jesús Barrero and Koji Wada.
- Screwed by the Network: According to an early article about the film, as well as the end of the pre-show video for the Fathom Events release of fellow Funimation-distributed film Dragon Ball Z: Resurrection F, The Boy and the Beast was supposed to get a nationwide release in early 2016. However, said release never wound up happening as planned and it was only released in a handful of theaters.
- Real-Life Relative: Kid Jirohiko's Latin American VA Cecilia Gómez is the stepdaughter of Jorge Roig Jr., who is the Latin American VA for Hyakushubo. Gómez's daughter, Abril, provided additional voices in the dub.
Trivia / The Boy and the Beast