Koisuru Alpha no Sodatekata

The prominent Kamimura family treasures all of their talented descendants. But this isn't the case for Nio, the only omega in the Kamimuras' long unbroken line of alphas. When the death of his brother Reo and sister-in-law Ruri forces Nio back to the house he left behind, their newly orphaned sons remind Nio of his past - especially the older brother Suou, who inherited Nio's brother's abilities despite not sharing any of his blood. What happens when these unlikely almost-relatives begin a new life together?

(Source: Fantasista Inc.)