Temple of Ranma's Sailor Senshi Seifuku

There's X-Change Students, by H. Torrance Griffin, a crossover with Generation X. To the best of my knowledge the fic is unfinished (and took a ridiculously long time for me to find).

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Shinji: Well suppose some mysterious entities were attacking, and
Asuka:Oh please, Baka Shinji, that sounds like some cheap, pseudo-profound T.V. show. Low budget. Ambiguous ending.
-Asuka and Shinji discussing why you would build a giant robot. NGE: Shinji Ikari Raising Project Vol.6

I don't know if necroing applies in this case. If so, I apologize.

Age of the War Horse is an AU where Ranma became the heir to En Sabah Nur aka the mutant known as Apocalypse. No mutant powers, just more of what Ranma already has plus leading the Horsemen in a war-for-the-darwinian-fun-of-it against, well, everyone. All the surviving good guys (from Nerima, Westchester and Latveria alike) are the ragtag La Resistance.