Transformation and Disguise in Palace of the Omega

Ilia, an omega, is sent to Hanu to marry the young king, Khalid. The young king is 10 years old but forms a friendship with Ilia and determines to eventually make him his consort. 

The plans are derailed when the king's brother Zayn carries out a coup. Both Khalid and Ilia are presumed dead after one is supposedly killed on a journey and the other jumps from a cliff.  

They find each other 8 years later and they have naturally undergone changes. Khalid's fundamental serious and charismatic character hasn't altered, but he is older and much taller. 

Ilia undergoes a change not in personality--he is still somewhat sarcastic and a bundle of concentrated intent--but in attitude. Though he starts out cynical and indifferent, he grows attached to Khalid for his youthful and innocent earnestness, for his devotion to Hanu, and for his total acceptance of Ilia as his consort and equal. Ilia becomes a believer in something. 

The character development is quite believable since it takes place over time and after personal interactions. 

The series also includes a disguise--namely, Khalid becomes the leader of the rebels without telling others his identity...except they aren't that surprised when he reveals himself...which amuses Ilia to no end. 

Good couple in a story with decent external and internal arcs! The transformations--quite a lot of them--make sense, and the characterizations remain consistent.