Masashi Amenomori was a Japanese actor and voice actor born on July 24, 1930, in Chiba Prefecture, Japan. A graduate of Nihon University's Department of Film, he began his career in theater, eventually becoming a founding member of the Theater Arts Association in 1970 before affiliating with the talent management firm Aoni Production. He passed away on April 9, 1984, at the age of 53.

Amenomori was a highly active voice actor from the early 1970s until his death, renowned for his work in numerous anime television series and films. He frequently voiced characters who were middle-aged men, including many supporting roles, villains, and comedic figures. His most iconic and representative role was as the father, Papa, in the long-running and popular Tensai Bakabon series, a part he played in both the 1971 original and the 1975 sequel, Ganso Tensai Bakabon. He also portrayed the father in the 1982 adaptation of Wagahai wa Neko de Aru, a role listed in the query as Beru.

His extensive filmography confirms many of the other roles mentioned in the query. He voiced the Cowardly Lion in the 1982 anime film The Wizard of Oz. In the 1979 special Undersea Super Train: Marine Express, he played Bunzo Marukubi. His role as Toragoro Onigawara in Hurricane Polymar (1974) and as Colonel Bull in Norakuro (1970) are also documented. He provided the voice for Baltac in Vicke the Little Viking (1974) and General Secretary Orlov in the 1982 film Future War 198X. His work in the Dr. Slump franchise includes the role of Gyaasuka Daimao in the. Slump & Arale-chan: Hello! Wonder Island. Earlier in his career, he played Kousuke Azuma in Animal 1 (1968) and Takao's Father in the 1983 anime Captain. Amenomori was also the voice of Michel in the 1975 adaptation of A Dog of Flanders and Mo (or Mou) in the 1978 series Future Boy Conan, directed by Hayao Miyazaki.

Beyond anime, Amenomori was prolific in Japanese dubbing of foreign films and television series. He was the regular Japanese dubbing voice for American actors Ward Bond and Fernando Sancho, and his many credits include dubbing roles in films such as The Godfather Part II, Some Like It Hot, and Zorro.

Throughout his career, Amenomori frequently collaborated with other prominent voice actors. His most frequent collaborator was Ichirō Nagai, with whom he worked on series like Future Boy Conan and A Dog of Flanders. He also worked repeatedly with actors such as Kaneta Kimotsuki, Kōji Yada, and Hideyuki Tanaka, and with director Isao Takahata on films like Gauche the Cellist.

Following his death from cirrhosis of the liver, several voice actors took over his ongoing roles, including Kōsei Tomita as the new voice of Papa in the Heisei version of Tensai Bakabon, and Shingo Kanemoto, who succeeded him in the role of Juliano in Ai Shite Knight.