Hakka Haien no Shujin to Shitsuji

Overview

Since escaping from a special child development center, Jougasaki Nanaki has been living on the streets, surviving only by stealing. A chance encounter with someone from his past leads him to a large, but run-down mansion on the outskirts of town. There, he meets a small boy and sees him disappear through a wall right in front of his eyes. Intrigued, Jougasaki remains on the grounds to become the household's butler in hopes of finding out the boy's secret, but...?

Source: AniList