Hana Himeru Kimi no Meteor

Synopsis:

“On that fateful night, I became the bride of a cursed monster…” Stella, the adopted eldest daughter of Viscount Quinwitch, lives a peaceful and loving life with her gentle family. That happiness is shattered when her younger sister, Lilinette, is chosen as the “Monster’s Bride.” Once every century, a cursed creature sealed within a castle demands a human sacrifice. Determined to protect her sister, Stella offers herself in Lilinette’s place and travels to the forbidden castle. There, she encounters the monster—Lavi, a bloodstained vampire whose existence is bound by an ancient curse. Thus begins a dark fantasy romance of sacrifice, fate, and forbidden love.