“Favorite supporting female anime character”
This is tricky because the one I named as my favorite female anime character already wasn’t the main character.
But I think I’ll say
Genkai from Yu Yu Hakusho. It’s rare for the mentor character in a shounen anime to be a woman, or for any fighting character in any anime to be an old woman. But age doesn’t seem to hold Genkai back, and not just because using her strongest technique makes her temporarily young again.
Which isn’t to say that age isn’t a major factor in her characterization. After all, her primary goal is to see her techniques passed on before she dies. And while she says she’ll teach the strongest no matter who it is, she does make it clear that she doesn’t really want an evil demon to win. So it’s not that she’s amoral, but she has another standard she holds higher than morals and ethics, and in a fairly interesting way.
Then she goes on to turn out to have a history with Toguro, to help Yusuke behind the scenes after he thinks she’s dead, and to be surprisingly good at video games.