Fushigi Yuugi, up to volume 10.

[snarp]

People had told me that this series stopped being a romantic comedy after a few volumes, but... I didn't expect all the villains to start raping the heroes to destroy their magical powers. I mean, I guess I can see it happening once, but it's become a recurring theme. They're literally standing around and discussing the finer points of the use of rape as a weapon, as characters in a shounen manga might discuss chi blasts.

...when I put it that way, it becomes clear to me that this manga is Sugar Sugar Rune's evil grandma.

Comments

[snarp]

Disempowerment-via-rape has been attempted three times so far - twice to Miaka and once to Tamahome - and Yui has been brainwashed into thinking that it's happened to her.

This is not something that the first couple volumes of the series would lead you to expect!

(double-posting this comment)

[torachan]

I did remember Yui's brainwashing, but I didn't remember that it had been a theme!