A “ghoul” was originally a creature in Arabic folklore that feasts on the flesh of the living or the dead, depending on the tale. The corpse-munching version became more popular in the West, but not in Japan, if Kentaro Hagiwara’s hair-raising “Tokyo Ghoul” is any indication.

Based on a manga by Sui Ishida, “Tokyo Ghoul” unfolds in an alternative modern-day Japan where humans uneasily coexist with ghouls who look and act like their human hosts, though they only consume human flesh. Ghouls live undercover with their own kind, which they identify by various marks such as tentacle-like organs called kagune that explode from their backs when they are roused to feed or fight.

Ken Kaneki (Masataka Kubota), a wimpy college boy, becomes a half-ghoul after a scary near-death experience. While keeping his ghoul side hidden from his best bud Hide (Kai Ogasawara), Ken struggles to win acceptance in the ghoul underworld, which is suspicious of his human side. Meanwhile he agonizes over his dual identity, beginning with his unconquerable craving for flesh.

This may make “Tokyo Ghoul” sound like a rip off of Takashi Yamazaki’s “Parasyte,” a 2014 SF/fantasy two-parter that also featured a trapped-between-two-worlds hero, a dystopian Japan and tentacles. But first-time director Hagiwara resists the sort of wretched excess found in the “Parasyte” films (particularly the histrionic second part), while keeping the action taut and the tension high.

Also, “Tokyo Ghoul” faithfully follows the outlines of the manga’s story, while depicting its characters, both ghoul and human, mostly in sympathetic shades of gray. Given the many scenes of ghouls voraciously chomping body parts as their owners scream and writhe, this understanding attitude may seem strange, but the film presents the ghouls’ dietary preferences more as a grim fate than sick kink.

Trying and failing to force normal food down his throat, the miserable Ken inspires a disturbing combination of horror and pity: It’s as if he’s spewing his very humanity on the kitchen floor. A standard-issue cinematic ghoul he is not, and his agony can be hard to watch.

For action fans with strong constitutions, however, “Tokyo Ghoul” serves up satisfying battles between Ken and his fellow ghouls and their human opponents. Among the former is Toka Kirishima (Fumika Shimizu), a fierce-eyed high school girl who works with Ken at a ghoul cafe — and who becomes his kick-ass martial arts mentor.

Among the latter are the silver-haired Mado (Yo Oizumi) and the towering Amon (Nobuyuki Suzuki), two cops belonging to an anti-ghoul unit. Equipped with exotic weaponry, they mercilessly pursue their quarry. The outcomes are seldom in doubt, but I was surprised to find myself rooting more for the ghouls than for humanity’s grim-faced defenders.

With its abundant use of creepy-looking CG, “Tokyo Ghoul” has obvious ambitions to lure local audiences away from Hollywood effects extravaganzas, but its basic message is anything but flashy. As William S. Burroughs once put it: “Beyond a certain frequency need knows absolutely no limit or control. In the words of total need: ‘Wouldn’t you?’ Yes you would.” Indeed.