Can I ask something?I'm not really quite versed in this manga and i've only watch the first season of the anime.
Is there any way to stop this tradition of girls being a priestess? And are there only two worlds connected?
No way to stop the girls from being priestess because it's their fate. Though the order of the time line goes:
Fushigi Yuugi: Genbu Kaiden
Fushigi Yuugi: Byakko Senki
then Fushigi Yuugi
I would recomend that if you want to read them you read them in the order they came out which is:
Fushigi Yuugi
Fushigi Yuugi: Genbu Kaiden
Fushigi Yuugi: Byakko Senki
You get more details and explanations that way
OMG.The never ending "ex-comes-back-trope" LUL
The author absolutely abuses that trope. And she makes sure the ex comes back right when things are starting to go well.