Adult PC Game: Fortune Sister by SLAVE RAVE Archive

Young girl Rieze (protagonist) lived with her friend Sufure in a small village.
Sufure was a shrine maiden of the wind; Rieze had inherited the hero Caldum's sword.
When a demon army invaded their kingdom, it began by destroying their home.
Rieze's little sister was taken prisoner, and on the verge of death herself
she was visited by Fortuna, the spirit of destiny.
Imbued with the spirit's energy Rieze set off on a journey: to save her sister.