My Slain Dragon Bride

The pinnacle of magic was the 9th Circle, a realm said to be that of a demigod. The final key to reaching it was the heart of the Crimson Dragon, Valdrova. “I never imagined my own fiancé would come to kill me.” Yet for some reason, Valdrova offered up her heart without putting up any resistance. “…What is this feeling? Why does this leave such a bitter taste?” Then I faced it—a despair far older and deeper than the hatred I had carried. — Description from novelcodex.org