Masaaki Yuasa has long established himself as one of the most creatively unbridled minds in all of modern animation — his expressionistic films (“The Night Is Short, Walk on Girl”) and television shows (“Devilman Crybaby”) alike exude a shape-shifting fearlessness that allows them to address old strifes with new sensitivities — but not even his die-hard fans could hope to adequately prepare themselves for the head-scratching, jaw-dropping, head-banging freak-out of the director’s latest and potentially last feature, “Inu-Oh.” An anime rock opera about a blind 14th century biwa player who becomes a massive star after teaming up with the “uniquely talented” Noh performer who lends the film its title (read: a hideous demon from hell who hides his disfigured face behind a gourd mask, breakdances with the help of his giant 10-foot arm, and daydreams about kidnapping children), “Inu-Oh” unfolds like a mash-up between the Japanese legend “The Tale of the Heike” and Queen’s “Bohemian Rhapsody,” right down to the Freddie Mercury falsetto. Not since 1973’s “Belladonna of Sadness” has an anime feature reimagined ancient history in such hypnotically psychedelic fashion.

At heart, “Inu-Oh” is a film about storytelling’s power to keep the past alive, and while Yuasa’s carnivalesque extravaganza can be too slippery to hold onto at times, it always proves unforgettable in a way that serves that ultimate purpose. Even viewers who are overwhelmed by the novel’s worth of opening text — an info-dense scrawl recounting the 12th century clash between the Genji and Heike clans — and puzzled by the political gamesmanship between rival imperial courts during Muromachi Era Japan will soon find themselves bopping along to the timeless beats of a tale about stolen myths, suppressed histories, and how the ghosts of the past make their voices heard. Transposed from Hideo Funrukawa’s 2017 novel “Tales of the Heike: Inu-Oh,” Yuasa’s adaptation begins 200 years after the  Heike’s slaughter at sea in the Battle of Dan-no-ura. The samurai clan’s surviving descendants have been huddled in hidden villages around the country since 1185, their ancestors’ memory passed down by a small handful of Biwa priests and Noh performers, and imbued into an even smaller number of sacred treasures that scream “don’t open me!” in a “Raiders of the Lost Ark” sort of way. Alas, some people just can’t resist the allure of a wooden box that’s covered in bloody handprints and buried at the bottom of the ocean. Tomona’s father is one such person; opening the artifact kills him, and permanently blinds his young son. Meanwhile, a woman gives birth to a shadow monster under a percussive storm of taiko drums as two very different lives begin their sprint toward a shared destiny.

 The first 15 minutes of “Inu-Oh” could almost pass for a “normal” movie, as Tomona (voiced by Mirai Moriyama) is trained by an old master and matures into a skilled biwa player while traveling the countryside in search of new stories to tell about his people. And then — in a sequence that recalls the opening havoc of Bong Joon Ho’s “The Host” — a little demon in a gourd mask scurries out of the sea and begins terrorizing everyone in sight (Inu-Oh is voiced by Avu-chan, the non-binary lead singer of rock band Queen Bee, and the role takes full advantage of their staggering musical range). Even as the monster laughs at the damage with the glee of an arsonist, you can see Yuasa’s love for this misunderstood creature in the balletic grace with which it jack-knifes through town on the strength of its wildly distended arm. The rampage only ends when Inu-Oh collides with Tomona, who literally can’t see what makes his new friend so fearsome to everyone else. The two outcasts naturally form a band and then — at around the 35 minute mark — rock this movie electric with their first performance of their instant hit single: A hyper-catchy cheese guitar banger about how Inu-Oh’s body was cobbled together from the remnants of 100 dead warriors. How nice that Tomona has found his ancestors. The spectacle of the movie’s subsequent musical numbers will put this one to shame, but the animated choreography is impressive even here, and Moriyama’s growl makes a beautiful one-two punch with Avu-chan’s elastic singing voice. From there, the rest of the film is an almost non-stop barrage of increasingly outsized jams, as Tomona and Inu-Oh grow so popular that their fame — and their increasingly androgynous appearances — begin to threaten the very foundation of the patriarchy itself. Yuasa has always displayed an affection for the marginalized and misunderstood, and that aspect of his art has never been more central than it is in the plot-light “Inu-Oh,” which maintains its narrative momentum by conflating personal and historical tendencies of erasure (a feeling that’s fully embraced by Taiyo Matsumoto’s evolving character designs). While the first act of “Inu-Oh” might seem to portend more conventional plotting, the last hour of the movie adheres to the mythic storytelling of pre-cinematic mediums. Dramatic scenes are largely eschewed in favor of soaring plot songs with outrageous visuals to match; watching a jammy tune combine Animal Collective-like yowls and a Taiko beat with images of a giant whale made out of fire, it’s easy to share in the crowd’s wild enthusiasm and understand the impact that star priests and performers were able to have on their public more than 600 years ago (Inu-Oh was a real person, though certain details about their life seem to have been slightly altered for dramatic purposes).

The self-immolating climactic sequence in which the duo reach the apex of their fame while railing against the empty pursuit of celebrity for its own sake combines ice dancing and flying dragons with a triumphant song in which Avu-chan’s voice pays a visit to every one of its many octaves. Even if the film sacrifices nuanced character detail and raw emotionality at the altar of its trans-centennial sweep, there’s a rare power to the ecstatic way in which Yuasa insists that history can never truly be re-written. Some songs will always be sung, even if they have to spend a few hundred years as neon blue crabs hiding inside human skulls and waiting for people to lend them a new voice.

Grade: B+

“Inu-Oh” premiered at the 2021 Venice Film Festival. GKIDS will release it in the United States in 2022. Sign Up: Stay on top of the latest breaking film and TV news! Sign up for our Email Newsletters here.