Otoshigo to Juusha no Monogatari

A slave with a fearsome appearance, Kustar was confined in a cage, expecting to die, until Julius, a strikingly beautiful and distant individual, purchased him to serve as a bodyguard. Julius, the second son of a concubine, is involved in multiple family disputes and frequently has to accommodate male guests. Over time, his initially aloof attitude toward Kustar, who is innocent and loyal, begins to shift as he gradually learns to soften his guarded heart.