The siblings aren't blood related. If I remember correctly.
No it was clearly established that they were not blood related
really wt page? i must of missed it. but regardless of blood they were raised like brother n sister, so its pretty disturbing to think about.... Speaking as 1 whom has a step sibling *Shivers* (⊙…⊙ )
http://www.mangago.zone/read-manga/almadianos_eiyuuden/nbt/9ef2ba91f52c9905/Vol1_Ch1/22/
And I'm pretty sure they re-explain it later but too lazy to look for it
And yes I get what your mean but the author seems to really want to go there --"
the plot seems interesting, I hope there is no incest though....(〜￣△￣)〜