Nope! They’re very good sisters who love each other.
btw this is part two of the story, the first part is somewhere else
I couldn't find the first part even though I read it here, I think it's in Japanese, so don't start reading this until you read the 12 chapters from that part I believe.
https://www.mangago.zone/read-manga/higeki_no_genkyou_tonaru_saikyou_gedou_rasubosu_joou_wa_tami_no_tame_ni_tsukushimasu/
here's the first part, with 17 chapters after all.
Pls spoil me . Will the original FL be a bitch like the other isekai stories? I kinda don't like those kind of plot