System: the Sister Who Fell from the Sky!

Xiao Yan was accidentally injured and died. After his rebirth, he suddenly had a little "sister" by his side! Since then, the two people have experienced various adventures together... If you bully my sister Mikasa, you will die! In short, it is a journey of conquest from a low-key and mysterious high school student to Mikasa's sister who can switch between cute and ruthless modes at will! This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.