If you went back in time and told the teenage me that “Lord of the Rings” would be getting an anime movie, you’d probably see me jump on the nearest table and revel like a drunken hobbit at the Green Dragon Inn. But “The Lord of the Rings: The War of the Rohirrim” proves that, like Gollum and the One Ring, some things are best kept apart.

J.R.R. Tolkien’s “Lord of the Rings” universe has a long history in animation, from Ralph Bakshi’s 1978 film to the TV versions of “The Hobbit” (1977) and “The Return of the King” (1980). But “The War of the Rohirrim,” directed by Kenji Kamiyama (“Ghost in the Shell: Stand Alone Complex”) is the first animated spinoff directly linked to Peter Jackson’s live-action film adaptations, even incorporating some of composer Howard Shore’s signature melodies from Jackson’s trilogy. It also boasts an impressive cast, from Miranda Otto, who narrates the tale as Eowyn, the character she played in the films, to Brian Cox of “Succession” fame.

Based on Tolkien’s vast “Lord of the Rings” appendices, the story takes place 200 years before “Rings” and tells the tale of Helm Hammerhand (Cox), the king of the Rohirrim (you know, the horse guys) in Rohan, and his daughter Hera (Gaia Wise).