Films: Ring (1998), Ring 2 (1999), Ring 0: Birthday (2000), Sadako 3D (2012), Sadako 3D 2 (2013), Sadako vs. Kayako (2016)
Location: Civilized Area/Haunted home
Height/Weight: That of an average human.
Summary: When people think of terrifying ghosts from the East, more times than often they are thinking of a stringy-haired maiden that can kill you just by giving you one dirty look. We have Sadako to thank for that imagery.
History: Once a sweet young girl, Sadako Yamamura was the daughter of a talented psychic who got driven to suicide after a disastrous demonstration that had the media denouncing her. The poor girl went into hiding after that, but was pursued by one of the doctors who was there and fired for believing in her. In a rage, this doctor stabbed her and left her for dead after throwing her into a well. After three decades, Sadako expired...but her rage against the world didn't. As a vengeful spirit, her own psychic powers became more powerful, and she placed most of her power into a cursed video tape detailing her prison and capable of killing a person in seven days. And the problem is that people keep passing this tape around, ensuring the cycle goes on forever.
Notable Kills: Anyone who has seen her true face dies of shock.
Final Fate: Sadako has managed to persist no matter how many times people try to break the curse. While her cursed tape hasn't reached a global scale, it has destroyed the lives of many, and could still do so. Oh, and there was that time she fused with another vengeful spirit, Kayako Saeki, and became Sadakaya, but how canon that was is up for debate.
Powers/Abilities: Can kill people through fear, as well as subtly manipulate reality.
Weakness: You need to watch the tape for her to kill you.
Scariness Factor: 4.5-Tragic backstory aside, Sadako is pretty much the apex of Japanese horror. Unstoppable, eternally wrathful, and above all, fantastically disturbing to look at. You can try and break the curse as many times as you can, but she'll come back, angrier than before. Oh, and she's managed to spread her influence to the internet...
Trivia: -The original film's "sequel", known as "Rasen", was so poorly received that it was stripped from continuity, and "Ring 2" was made instead.
-Sadoko seems to be based mostly on the old Japanese ghost story of Okiku, a fair maiden who was thrown into a well to her demise after not reciprocating a samurai's advances. She too rose as a spirit, an Onryo, and only stopped haunting if someone could help her with her torment.