Umi no Yami, Tsuki no Kage

These OVAs are from the 80s. They feature a girl that wants to kill another girl for romantic purposes but all of this is done by a supernatural power those girls get. Something to check out if you are into old anime. 

In general, the similarity of these anime is that the heroes of the anime, hitting a certain area, are under the influence of so-called curse. In Higurashi, it is called - "The Curse of Oyashiro-Sama", but Umi no Yami, Tsuki no Kage called "The Curse of Tutanhamon's". Also, those cursed to be a physical explanation is that this is some bacteria, cat. alter the consciousness of the brain. Accordingly, people exposed to this curse begin to lose their sanity and give vent to his goals and desires. And on the way to achieving its goal will not stop at nothing, even before the native twin sister. Blood and dismemberment attached. ^__^ read more