Ichigo Aika: Zatsu de Namaiki na Imouto to Warikirenai Ani

Kouta's life changes when his father remarries and Aika becomes his new stepsister. In front of their parents, Aika plays the sweet, perfect daughter, but behind closed doors her brash and provocative personality comes out, turning life with Kouta into a daily war of arguments.

Over time, hostility gives way to an attraction neither knows how to handle, making their new family boundaries far more complicated than expected. Their relationship moves through jealousy, rivalry, and confusing closeness as both struggle to decide whether what draws them together is a passing impulse or something they cannot simply ignore.