Even for a Hikiko-san film, there are a lot of bullies. Welcome to a J-horror film with an entire classroom full of deserving victims. Result: this one's good, violent fun. I enjoyed it.
HIKIKO-SAN = this is at least the fifth Hikiko-san film from this director (Scream Girls, Scream Girls 2, Hikiko-san vs. Kuchisake-onna, Hikiko-san vs. Kokkuri-san), so unsurprisingly he's more interested in her and does into all her lore. She drags people to death. She hates bullies. She's disfigured. The film even teases us with a bit of rain. She's presented as more powerful than Sadako... hell, she's more powerful than three Sadakos. Furthermore, there's the question of whether or not she's benevolent. Does killing bullies make her the victims' friend? Or is she bad news for them too? Sadako has a dark view on this, but she's hardly an unbiased source.
SADAKO = on the other hand, Sadako's lore is way off. The title presumably wants us to think she's Sadako Yamamura from Ringu (i.e. the runaway most successful J-horror film ever)... but she's not. Maybe they tried, but couldn't get the rights? They're taking inspiration from a real psychic called Sadako Takahashi who also inspired Ringu... but even that's carefully ambiguous, since this film's Sadako's surname is Takamura. (It's a portmanteau of "Takahashi" and "Yamamura".)
Anyway, this Sadako is one of three psychics who committed suicide many years ago. But they'll be back.
The bullies are vile. They use a drawing pin to attach a piece of paper saying "die" to their victim (Shiori). The teacher ignores bullies throwing things at Shiori in class, so I wanted her dead too. In fact, the entire class seems to be ganging up on their chosen victim, bar one brave girl (Nagisa) who tries and fails to defend her. The girls pull off her shirt, the boys lift her skirt and later there's a gang-rape. (Ordered by a girl, but so confusingly shot that it's not obvious what actually happened. No nudity, for instance.)
Shiori's parents are almost as bad. They're Japanese white trash. They punch Shiori in the stomach, treat her as a slave and then complain about the food they forced her to cook.
The film then becomes cartoonish whenever we meet the wacky hypnotist and his two lesbian assistants. The latter one point make it harder to concentrate on the hypnotist's exposition. They're all played so broadly that it's high camp, or even parody. You'd almost expect Disney cartoon animals to appear and start singing.
Even apart from them, though, the whole thing's over-the-top and sometimes ludicrous. One of the (female) bullies claims to be in love with Shiori and says she was only bullying her to attract her attention. Erm, no. The film expect us to take this seriously, but no. The film bulldozed past the last point of plausibility on that within about ninety seconds. (The acting isn't strong enough to support it either.) That was unintentionally hilarious. It is, though, cool to see four J-horror ghouls going apeshit, both on humans and against each other. Killing Shiori's parents? Good work, undead psycho girl. (Mum's minimal reaction after Dad's death is jaw-dropping.) Then, Sadako vs. Hikiko made me laugh.
The ending's dark, though. The most poignant interpretation of Hikiko's motivations might be that she wants to send them home, but can't.
This film contains: (a) two likeable characters, (b) four highly entertaining mass-murdering undead, and (c) a despicable horde of scum who deserve what's coming. Mind you, even Nagisa and Shiori aren't saints. Nagisa prays to Hikiko-san to come and kill all the bullies, which probably counts as mass murder even if we want that too. Anyway, it's a laugh.