Isekai One Turn Kill Neesan: Ane Douhan no Isekai Seikatsu Hajimemashita

High school otaku Asahi Ikusaba's mundane life takes a fantastical turn when he is miraculously transported to a magical world—a world he has only dreamed of from his beloved games and novels. Initially thrilled, Asahi soon discovers that unlike the heroes in his fantasies, he possesses no special powers. Just as he faces a life-threatening encounter, his sister, Maya, appears with the overpowering abilities he lacks. With her immense powers and a deep devotion to her brother, Maya becomes Asahi's guardian in this unpredictable realm.

The siblings navigate their new reality with Maya's extraordinary skills at the forefront, battling beasts and thwarting dangers that lurk around every corner. As they explore the mystical world, they learn that their presence might be more than mere chance, especially with the looming threat of the Demon King's army. Together, Asahi and Maya must uncover the purpose behind their journey to this world, all while trying to find a way back home.