Old School for Younger Readers!

[Shepherd]

That infamous one where Akane kills Ranma due to rage disorder, except that it's horrible and should not be recommended to anybody. It pretty much does define the genre of "Ranma turned grimdark by treating it realistically instead of as a slapstick comedy," though.

I'd forgotten about that one. For a different - and equally disturbing - Ranma darkfic, you've got "Ill Met By Starlight," where Ranma went crazy because Genma never finished putting him through the catfist training. Spoiler: most of the cast dies by the end.

Ranma Saotome is invincible

If it's got martial arts in it, he'll win, eventually
This is a good thing....right?

What if things had gone a little differently, though?
One day, one different decision,
one event out of place,
changing....
cascading....
What if Ranma wasn't the hero, but the villain?

Ill Met by Starlight
By Susan Doenime and Mike Loader

The original website is either temporarily or permanently down, but it looks like someone made a copy of it and a bunch of other old fics here:
http://web.archive.org/web/2003071110401...shop/2939/

Of those fics, "Relentless" is complete on the author's original page. Happosai interrupted a funeral, so now has an unstoppable supernatural monster after him. He tricks it into targeting Ranma instead.

A tale of power, gags, and intense vengeance...

http://talesfromthevault.com/relentless/


There is also Fire's "Destiny's Child".

What if, Ranma had been born during the 1600's, and on his visit to Jusenkyo, he fell into the spring of Drowned Young Girl. Now, when he is splashed with cold water he turns into a 12 year old girl that never ages, and the only way for him to turn back is with nearly boiling water.

https://www.fanfiction.net/s/26926/1/Destinys_Child