Thanks for replying-- and yes, extensive training is the most legitimate reason I can think of-- but time skips are sort of iffy. For instance, Running Up That Hill by TheHatterTheory is a great fic and it shows in detail how Kagome comes to be so powerful. No "she had a dream and became enlightened" or "Sango had taught her all the skills of demon slayers" because the latter is kind of ridiculous; how can Sango pass on a lifetime of knowledge in a couple years?
Sorry for ranting; it's just one of my pet peeves about Kagome fanfiction.
And as for being turned into a youkai, I usually don't like those, like "she woke up and became a demon" or something like that. But I can see myself enjoying something fun and reasonable. Demi-goddess? Why not?
EDIT BY WICCAN: "Running Up That Hill" is rated MA, NO YIMs!