Aniki to Issho ja Nemurenai

Synopsis

Eight years ago, our parents remarried and we became brothers. Haruto is six years older than me. We're not related by blood, but he treats me kindly and takes care of me as if I were his real brother. Because of this, I started harboring this desire to monopolize him... I don't want him to find out about these dirty feelings! Although I live alone now that I started university, my brother found a way to come after me...!? (Source: Exiled Rebels Scans)

Anime adaptations