I've come to that happy point in one story I'm working on where I need to start tracking down people to play beta-reader for me...
The story is set in the Yami no Matsuei fandom, but the principal characters are OC's because it was originally conceived as a piece of original fiction. The central plot is about a salaryman named Maruyama Jurou who schemes to abduct and murder a random girl, and what happens when the girl he kills- a secondary high school student named Watanabe Masami- fails to die the way she should have, and instead becomes an onryō: a type of Japanese ghost that attacks just about everyone it can reach, in order to get revenge for the wrongs that were done to them. (Ju-On's Kayako and Ringu's Sadako are perfect examples of such ghosts, btw.)
My belief about conventional onryō is that these ghosts are psychologically unable to remove themselves from whatever was happening when they died, and are, for whatever reasons, unable to tell the difference between random people and the people who wronged them. They also suffer from anterograde amnesia, so for them, every kill is their first, and every kill is, at least in the onryō's mind, committed while lashing out in self-defense. They also lack a great deal of self-awareness; their anterograde amnesia is severe enough that, effectively, they are constantly reliving their last moments, which keep them from being able to take their attention off of their own pain long enough to notice what's going on.
Masami is a bit different. For a short time she is subject to these psychological limitations, but they begin to wear off not long after her death. At the same time, Tsuzuki and Hisoka have been dispatched to track her down; her family and friends are all panicking over what might have happened to her; her murderer is panicking because he had a close call with Masami's ghost; and his wife, kids, and coworkers are all wondering what's up with him. Everything else unfolds from there.
I am currently fretting miserably over the first chapter of this story, and I'd really love it if anyone would be willing to read over my work and give me feedback on what I can do to improve it. ^^;; Even if you aren't in the Yami no Matsuei fandom, I think it should be fine; although the two leads from that series are main characters, they aren't the main characters. A lot of story time will probably be devoted to what Jurou's wife and kids go through in the wake of his crime, for example.
ETA: I should point out that this story isn't intended as a thriller or a horror story, and I only plan to include as much gore as is needed for the plot.