hunting the emperor maybe?? the FL hair isnt black tho
empress hunt** mbb
its not this one :( its a manga unfortunately !! i think the title had something to do with the sister and the fiance, but i cant remember.
don't know if you wanted to know but i found it ! it's this(▰˘◡˘▰)
https://www.mangago.zone/read-manga/the_person_i_loved_asked_me_to_die_in_my_younger_sister_s_place/
hellooo does anyone know this manga where the fl goes to another dimension to fight ? there was like magic or something inside and she had to fight to prevent from harming the other world. i think she also gives her fiance to her sister. she had black hair and met a guy in the other dimension ! (▰˘◡˘▰)