I recall reading a fic with a developing ranma & urd pairing. Ranma finds Urd in the Morisato residence, but they both leave after exchanging a few lines (despite being clearly besotted with each other). Urd spends a chapter trying to find Ranma's name and location (getting his file from Peorth??). Being in Urd's presence has a profound effect on Ranma (who drops to his knees at times)
Other details: In a chapter Ranma was working on a technique that allowed river water to pass through his body, using something similar to Mousse's hidden weapons pockets.
Hint: Read this fic on fanfiction.net, perhaps a multi-cross?
Any suggestions much appreciated.