Houkai Tenshi Astraea

Shikui. The life of my sister and I changed forever since we learnt of their existence. While we were not peculiarly happy, we were supposed to live ordinary and peaceful days. Even that evening, after buying ingredients for my favorite hamburger steak, my younger sister Hina and I were coming home leisurely when we saw a weird silhouette crouched in front of our house's entrance. The octopus-like creature suddenly swelled up and sent us flying with overwhelming strength. While desperately holding Hina in my arms in a panic, it was clear to my mind that we were going to die. "You stop right there!" At that moment, a voice like the ones you hear only in hero stories made itself heard. However, because what appeared wasn't a dependable and mysterious hero but my classmate Aihara Nozomi, I thought that the number of victims would only increase now and stood in front of her as to protect her-- "You really want to help? Alright, let's do this. Don't move!" "Eeh, uooooooooh!!??" My body melted and I felt like I was sucked up somewhere-- "(What's going on!? Am I going to die, after all!?)" Finally, before I knew it, I had merged with Aihara's body and we had repelled the octopus monster. "Yesssss! The Star Maiden won!" Aihara with whom I had merged, wearing a costume resembling the one of a majokko anime, was taking a victory pose. That was the moment my ordinary days ended.