Kashikomarimashita, Destiny
Complete | Sachimo | 2015 released
One of the best omegaverse stories I ever read. Though Aoi [Ω] is the eldest son of Toujou Family, but being an Omega boy - lowest rank of race, his dad even treated his stepmom over him. After his dad's gone, Aoi had to leave the house with his loyal butler Miyauchi [B]. The Saionji Family Head who owed Aoi's parents, took him in to work as apprentice butler. The heir Jirou [∝] & butler Kudou [∝] who're proud of their predominant Alpha & insulting Omegas, against it.
Unmei no Kisu wa Oazuke