Palace of the Omega, Vol. 2 by Fumi Tsuyuhisa

The omega prince of a poor nation has been sold off to a wealthy alpha king for political and financial gain, but all is not as it seems. Ilya, the 13th prince of a small kingdom, was born an unexpected-and very much unwanted-omega whose birth brought shame upon his royal family. As the lowest-ranking member and an omega, he is destined for a political marriage meant to improve his kingdom's standing. Unfortunately, Ilia's new life continues to be tumultuous-his husband has been assassinated, and a civil war has erupted in his new home country. But after eight long years of fighting, an encounter with a mysterious yet familiar young man will change his future forever.
Binding: Paperback / softback