Imouto ni Konyakusha wo Yuzure to Iwaremashita, Saikyou no Ryuu ni Kiniirarete Masaka no Oukoku Nottori?

Eliana had hoped to become the prince's fiancée, but her younger sister unexpectedly wins the position after falling in love with him, with the approval of their father and the king. In response, Eliana attempts to sacrifice herself by jumping into magma, seeking to become the "Dragon Bride." Instead of dying, she is rescued by the legendary dragon Greed, who takes her to his lair and decides to marry her as the legend suggests. Eliana begins her new life as the dragon's bride.