Isekai One Turn Kill Nee-san: Ane Douhan no Isekai Seikatsu Hajimemashita

"It wasn't me who was the strongest in another world, but my sister?!" As a result of an accident in the real world, Asahi Ikusaba is transported to another world. He tries to enjoy the different world he imagined, but his abilities prove to be the weakest. Just as he's about to be attacked by a vic