Films: Ju-on: The Grudge (2002), Ju-on 2 (2003), Ju-on: The Beginning of the End (2014), Ju-on: The Final (2015), Sadako vs. Kayako (2016)
Alias: Kayako and Toshio Saeki, Mar the cat
Location: Haunted home/Civilized Area
Height/Weight: That of average humans/a cat.
Affiliation: Neutral, leaning on Evil
Summary: It seems that Japan loves creating horrific stories of women scorned rising from the dead and torturing the living. It's most prized horror icons, Sadako included, fit the bill perfectly. But if Sadako is Jason Voorhees, then Freddy Krueger comes in the form of these two vengeful spirits.
History: Kayako Saeki was always an anti-social sort of person. Her isolation was her burden until she met and married the seemingly kind Takeo. Unfortunately, Takeo went mad with jealousy upon suspecting that Kayako was seeing someone else, and brutally murdered her before leaving her son Toshio to die in the attic and kill their cat Mar with a knife. But Kayako's rage persisted beyond death, and now, she and Toshio carry the Ju-on curse, which means that their combined rage gives them the power to stay at their house in Nerima, Japan to haunt those who dare enter. Some come out feeling alright until a long time later, where they are killed by these Eastern revenants. Then again, the third film reboots Kayako into a truly vindictive monster who openly gloats about her murders and Takeo's failings, as well as Toshio not even being her own son and instead the real perpetrator of the curse, so none of that sh*t is canon to us.
Notable Kills: One person gets their lower jaw ripped off! Also, Kayako kills everyone in the room AFTER emerging reborn out of a woman's womb...non-fatally. She later pushes that woman off of a bridge under the guise of a normal little girl.
Final Fate: The curse will never die. People can run from it, delay it, but destiny arrives. Kayako and Toshio will forever plague Japan with their murderous rage, even after the long-thought-dead Takeo was vanquished by Kayako. Oh, and there was that one time where Sadako and her fought and then fused, but again, who's calling that canon?
Powers/Abilities: Invincibility, immortality, manipulation of reality.
Weakness: Toshio doesn't kill, he just exists as an omen to really bad things. Aside from that, none.
Scariness Factor: 5-Sadako is one thing, but now there's a whole family of ghosts to worry about. Aside from utterly tragic backstories, the Saeki family is something to behold, with people dying at Kayako's hands in a number of inescapable and horrible ways. That croaking noise will haunt you forever...
Trivia: -Kayako is a straight example of an Onryo, a vengeful Yokai whose name translates to "wrathful spirit", and is created when someone dies a horrible death, and is literally too angry to die. Sometimes, Onryo were said to not only kill, but create natural disasters in their rage!
-Kayako's original actress, Takako Fuji, actually can do that incredibly creepy four-legged walk that Kayako does without any need for outside effects, and has used it as a prank for many a party.