Yakeppachi Sekai Seifuku

The hero, an archer and I have departed on a journey to defeat the demon king. At some point, I realized I'm so in love with the hero my heart just won't stop pounding! I don't even care about defeating the demon king anymore! I gathered my courage and told him how I felt, but... "I love you too. Like a little sister." ...wait, what? Little sister? Are you kidding me?!