Ore no Imouto ni Te, Dasu na!

After intense studying, the protagonist managed to enter a prestigious school in the countryside and gain the right to live alone. He was finally enjoying his carefree solitary life, but his cute yet sassy younger sister appeared, turning his solo life upside down! Now, the cohabitation of the eccentric older brother and the cheeky younger sister begins, and who knows how things will turn out...

[Translated from DLsite]