“All Middle-earth knows the tale of the War Of The Ring,” moodily intones Miranda Otto’s Cate Blanchett-esque voiceover at the beginning of The War Of The Rohirrim. But the story of Helm Hammerhand and his daughter Hèra, we are told, is “not a song you will have heard sung”. That’s partly because it’s a tale plucked from the depths of J.R.R. Tolkien’s appendices, set two centuries before Frodo was even a twinkle in Sauron’s Great Eye. It is almost literally a footnote, a feeling this spin-off film sometimes struggles to shake off — despite some impressive work.

Directed by Japanese anime master Kenji Kamiyama, this is the first Middle-earth feature-length film in a decade, and the first major animated outing for the series since Ralph Bakshi’s psychedelic 1978 adaptation. It’s an interesting match-up of people behind the camera — an odd fellowship of strangers from distant lands,...