This is an odd story in several respects. For one it has none of the usual Ranma tone. It's creepy psychotic suspense. For the second Nabiki is actually written as an in character near Complete Monster!
That almost never happens... although mostly without the characteristic upbeat goofy snark that gave her charm
. For the third Ranma is at least as bad
. For the fourth, it was still written well enough to not make you care.